3d printing devices and methods

ABSTRACT

A device is provided for making an implant having a hollow region, the device comprising a print surface rotatable in a clockwise and counterclockwise direction about an axis of rotation; a print head disposed adjacent to and substantially transverse to the print surface, the print head configured to apply material used to make the implant on at least a portion of the print surface or heat material disposed on at least a portion of the print surface used to make the implant; and a base disposed adjacent to the print head and contacting the print surface, the base configured to be movable in forward, backward and lateral directions relative to the print head to make the implant having the hollow region. Methods of using the device and are also disclosed.

BACKGROUND

3D printing technology is applied in various industries formanufacturing and planning. For example, the automotive, aerospace andconsumer goods industries use 3D printing to create prototypes of partsand products. 3D printing has also been used in the architecturalindustry for printing structural models. The applications of 3D printingin private and government defense have grown rapidly as well.

3D printing has had a significant impact in the medical fields. Medicalapplications of 3D printing date back to the early 2000s, for example,with the production of dental implants and prosthetics. 3D printing hasalso been used in the fabrication of drug delivery devices that can beused for direct treatment. A variety of drug delivery devices may becreated which allow for customizable drug release profiles.

Traditional 3D printing allows an object to be created by depositing amaterial over a flat fabrication platform one layer at a time. Once afirst layer is deposited, a second layer is deposited on top of thefirst layer. The process is repeated as necessary to create amulti-laminate solid object. However, 3D printing does not allow forcontinuous extrusion to create an object.

Conventionally, bone tissue regeneration is achieved by filling a bonerepair site with a bone graft. Over time, the bone graft is incorporatedby the host and new bone remodels the bone graft. In order to place thebone graft, it is common to use a monolithic bone graft or to form anosteoimplant comprising particulated bone in a carrier. The carrier isthus chosen to be biocompatible, to be resorbable, and to have releasecharacteristics such that the bone graft is accessible. Generally, theformed implant, whether monolithic or particulated and in a carrier, aresubstantially solid at the time of implantation and thus do not conformto the implant site. Further, the implant is substantially complete atthe time of implantation and thus provides little ability forcustomization, for example by the addition of autograft.

Traditional methods of 3D printing allows for objects to be createdthrough layered stratification of print material onto a flat surface.The layered stratified products created through traditional 3D printinglack the strength and flexibility necessary to make a hollow implant. Assuch, a suitable implant having a hollow center for particulated bone orother osteogenic materials is difficult to manufacture throughtraditional 3D printing methods.

Thus, there is a need for a 3D printing device that can manufacturehollow structures for implantable medical devices, such as for example,mesh covering or bags that are strong, flexible, stretchable andbiocompatible. There is a need for a 3D printing device having arotatable printing surface that allows continuous extrusion instead ofstratified layers to manufacture hollow structures for implantablemedical devices.

SUMMARY

Provided are 3D printing devices and methods of use for creating hollowstructures such as mesh bags. Also provided are 3D printing devicesincluding a rotatable printing surface to create such hollow structures.Further provided are devices and methods for 3D printing onto such arotatable printing surface by continuous extrusion instead of stratifiedlayers. Additionally, provided are devices and methods for creatingstructures having a meshed design that are strong, flexible, stretchableand biocompatible. In some embodiments, because the implant is printedcontinuously, there is no need to seal all sides of the implant, at mosttwo sides or one side of the implant.

According to one aspect, provided is a device for making an implanthaving a hollow region, the device comprising a print surface rotatablein a clockwise and counterclockwise direction about an axis of rotation;a print head disposed adjacent to and substantially transverse to theprint surface, the print head configured to apply material used to makethe implant on at least a portion of the print surface or heat materialdisposed on at least a portion of the print surface used to make theimplant; and a base disposed adjacent to the print head and contactingthe print surface, the base configured to be movable in forward,backward and lateral directions relative to the print head to make theimplant having the hollow region.

According to another aspect, provided is a device for making an implanthaving a hollow region, the device comprising a print surface rotatablein a clockwise and counterclockwise direction about an axis of rotationrelative to a print head, and at least one of (i) the print surfaceconfigured to be movable in forward and backward directions relative tothe print head or (ii) the print head configured to be movable inforward and backward directions relative to the print surface, the printhead disposed adjacent to and substantially transverse to the printsurface; and the print head configured to apply material used to makethe implant on at least a portion of the print surface or heat materialdisposed on at least a portion of the print surface used to make theimplant having the hollow region.

According to yet another aspect, provided is a method for making animplant having a hollow region, the method comprising applying amaterial used to make the implant having the hollow region on a devicehaving a print surface, the device having the print surface rotatable ina clockwise and counterclockwise direction about an axis of rotation, aprint head disposed adjacent to and substantially transverse to theprint surface, the print head configured to apply the material used tomake the implant on at least a portion of the print surface or heatmaterial applied on at least the portion of the print surface used tomake the implant, a base disposed adjacent to the print head andcontacting the print surface, the base configured to be movable inforward, backward and lateral directions relative to the print head tomake the implant having the hollow region.

According to yet another aspect, provided is a computer-implementedmethod for creating hollow structures, the method comprising inputtinginstructions to direct a processor, the processor configured to inducerotation of a print surface in alternating clockwise andcounterclockwise directions, and ejection of material from a print headto the print surface to make a strand having a wave-like pattern withalternating peaks and crests, and rotating the print head such anangular distance to create a plurality of interconnected strands on theprint surface.

While multiple embodiments are disclosed, still other embodiments of thepresent application will become apparent to those skilled in the artfrom the following detailed description, which is to be read inconnection with the accompanying drawings. As will be apparent, thepresent disclosure is capable of modifications in various obviousaspects, all without departing from the spirit and scope of the presentdisclosure. Accordingly, the detailed description is to be regarded asillustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of an exemplary 3D printing deviceaccording to an aspect of the present application. The 3D printingdevice includes a rotatable printing surface to facilitate continuousextrusion of a predetermined hollow implant.

FIG. 2 illustrates a perspective view of components of an exemplary 3Dprinting device according to an aspect of the present application.Specifically, shown is a printing surface having a cylindrical shapeconfigured to create a cylindrically shaped hollow structure, such as amesh bag. The printing surface is adjacent to and/or contacts a printhead.

FIG. 3 illustrates a perspective view of components of an exemplary 3Dprinting device according to an aspect of the present application.Specifically, shown is a printing surface having a rectangular crosssection configured to create a rectangular or square shaped hollowstructure, such as a mesh bag.

FIG. 4 illustrates a perspective view of an exemplary hollow structurecreated through use of a 3D printing device, according to an aspect ofthe present application. The depicted hollow structure includes arectangular cross section.

FIG. 5 illustrates a perspective view of components of an exemplary 3Dprinting device according to an aspect of the present application.Specifically, shown is the movement of a printing surface while a printhead, such as, for example, an applicator continuously extrudes materialto the surface to form a mesh pattern.

FIG. 5A illustrates a perspective view of a mesh bag having a hollowinterior region formed from a 3D printing device according to an aspectof the present application.

FIG. 5B illustrates a perspective view of a mesh bag as in FIG. 5Acontaining an osteogenic material in the hollow interior region.

FIG. 6 illustrates a side view of components of an exemplary 3D printingdevice according to an aspect of the present application. Specifically,shown is a print head which processes material to be extruded to theprinting surface.

FIG. 7 illustrates a side view of components of an exemplary 3D printingdevice according to an aspect of the present application. Specifically,shown is a radiation source, such as, for example, a laser mountedadjacent the print head to apply an energy to sinter or melt thematerial discharged from the print head.

FIG. 8 illustrates an embodiment of a computer-implemented system forproducing a hollow structure, such as a mesh bag.

FIG. 9 is a flow diagram illustrating an embodiment of thecomputer-implemented system for producing a hollow structure, such as amesh bag.

FIG. 10 is a flow diagram illustrating an embodiment of a system forproducing a hollow structure, such as a mesh bag, through the use of a3D printing machine having a rotating printing surface.

It is to be understood that the figures are not drawn to scale. Further,the relation between objects in a figure may not be to scale, and may infact have a reverse relationship as to size. The figures are intended tobring understanding and clarity to the structure of each object shown,and thus, some features may be exaggerated in order to illustrate aspecific feature of a structure.

DETAILED DESCRIPTION Definitions

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities of ingredients,percentages or proportions of materials, reaction conditions, and othernumerical values used in the specification and claims, are to beunderstood as being modified in all instances by the term “about.”Similarly, when values are expressed as approximations, by use of theantecedent “about,” it will be understood that the particular valueforms another embodiment that is +/− 10% of the recited value.Accordingly, unless indicated to the contrary, the numerical parametersset forth in the following specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the present disclosure. At the very least, andnot as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques. Also, as used inthe specification and including the appended claims, the singular forms“a,” “an,” and “the” include the plural, and reference to a particularnumerical value includes at least that particular value, unless thecontext clearly dictates otherwise. Ranges may be expressed herein asfrom “about” or “approximately” one particular value and/or to “about”or “approximately” another particular value. When such a range isexpressed, another embodiment includes from the one particular valueand/or to the other particular value.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of this application are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Moreover, all ranges disclosed hereinare to be understood to encompass any and all subranges subsumedtherein. For example, a range of “1 to 10” includes any and allsubranges between (and including) the minimum value of 1 and the maximumvalue of 10, that is, any and all subranges having a minimum value ofequal to or greater than 1 and a maximum value of equal to or less than10, e.g., 5.5 to 10.

Bioactive agent or bioactive compound is used herein to refer to acompound or entity that alters, inhibits, activates, or otherwiseaffects biological or chemical events. For example, bioactive agents mayinclude, but are not limited to, osteogenic or chondrogenic proteins orpeptides, anti-AIDS substances, anti-cancer substances, antibiotics,immunosuppressants, anti-viral substances, enzyme inhibitors, hormones,neurotoxins, opioids, hypnotics, anti-histamines, lubricants,tranquilizers, anti-convulsants, muscle relaxants and anti-Parkinsonsubstances, anti-spasmodics and muscle contractants including channelblockers, miotics and anti-cholinergics, anti-glaucoma compounds,anti-parasite and/or anti-protozoal compounds, modulators ofcell-extracellular matrix interactions including cell growth inhibitorsand antiadhesion molecules, vasodilating agents, inhibitors of DNA, RNAor protein synthesis, anti-hypertensives, analgesics, anti-pyretics,steroidal and non-steroidal anti-inflammatory agents, anti-angiogenicfactors, angiogenic factors, anti-secretory factors, anticoagulantsand/or antithrombotic agents, local anesthetics, ophthalmics,prostaglandins, anti-depressants, anti-psychotic substances,anti-emetics, and imaging agents. In certain embodiments, the bioactiveagent is a drug. Bioactive agents further include RNAs, such as siRNA,and osteoclast stimulating factors. In some embodiments, the bioactiveagent may be a factor that stops, removes, or reduces the activity ofbone growth inhibitors. In some embodiments, the bioactive agent is agrowth factor, cytokine, extracellular matrix molecule or a fragment orderivative thereof, for example, a cell attachment sequence such as RGD.A more complete listing of bioactive agents and specific drugs suitablefor use in the present application may be found in “PharmaceuticalSubstances: Syntheses, Patents, Applications” by Axel Kleemann andJurgen Engel, Thieme Medical Publishing, 1999; the “Merck Index: AnEncyclopedia of Chemicals, Drugs, and Biologicals”, edited by SusanBudavari et al., CRC Press, 1996; and the United StatesPharmacopeia-25/National Formulary-20, published by the United StatesPharmacopeia Convention, Inc., Rockville Md., 2001, each of which isincorporated herein by reference.

Biocompatible, as used herein, is intended to describe materials that,upon administration in vivo, do not induce undesirable long-termeffects.

Bone, as used herein, refers to bone that is cortical, cancellous orcortico-cancellous of autogenous, allogenic, xenogenic, or transgenicorigin.

Bone graft, as used herein, refers to any implant prepared in accordancewith the embodiments described herein and therefore may includeexpressions such as bone material and bone membrane.

Demineralized, as used herein, refers to any material generated byremoving mineral material from tissue, for example, bone tissue. Incertain embodiments, the demineralized compositions described hereininclude preparations containing less than 5% calcium. In someembodiments, the demineralized compositions may comprise less than 1%calcium by weight. In some embodiments, the compositions may compriseless than 5, 4, 3, 2 and/or 1% calcium by weight. Partiallydemineralized bone is intended to refer to preparations with greaterthan 5% calcium by weight but containing less than 100% of the originalstarting amount of calcium. In some embodiments, partially demineralizedbone comprises 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91,92, 93, 94, 95, 96, 97, 98 and/or 99% of the original starting amount ofcalcium.

In some embodiments, demineralized bone has less than 95% of itsoriginal mineral content. In some embodiments, demineralized bone hasless than 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81,80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63,62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45,44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27,26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9,8, 7, 6 and/or 5% of its original content. In some embodiments,“Demineralized” is intended to encompass such expressions as“substantially demineralized,” “partially demineralized,” “surfacedemineralized,” and “fully demineralized.” “Partially demineralized” isintended to encompass “surface demineralized.”

In some embodiments, the demineralized bone may be surface demineralizedfrom about 1-99%. In some embodiments, the demineralized bone is 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58,59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76,77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94,95, 96, 97, 98 and/or 99% surface demineralized. In various embodiments,the demineralized bone may be surface demineralized from about 15-25%.In some embodiments, the demineralized bone is 15, 16, 17, 18, 19, 20,21, 22, 23, 24 and/or 25% surface demineralized.

Demineralized bone activity refers to the osteoinductive activity ofdemineralized bone.

Demineralized bone matrix (DBM), as used herein, refers to any materialgenerated by removing mineral material from bone tissue. In someembodiments, the DBM compositions as used herein include preparationscontaining less than 5% calcium and, in some embodiments, less than 1%calcium by weight. In some embodiments, the DBM compositions includepreparations that contain less than 5, 4, 3, 2 and/or 1% calcium byweight. In other embodiments, the DBM compositions comprise partiallydemineralized bone (e.g., preparations with greater than 5% calcium byweight but containing less than 100% of the original starting amount ofcalcium).

Osteoconductive, as used herein, refers to the ability of a substance toserve as a template or substance along which bone may grow.

Osteogenic, as used herein, refers to materials containing living cellscapable of differentiation into bone tissue.

Osteoinductive, as used herein, refers to the quality of being able torecruit cells from the host that have the potential to stimulate newbone formation. Any material that can induce the formation of ectopicbone in the soft tissue of an animal is considered osteoinductive. Forexample, most osteoinductive materials induce bone formation in athymicrats when assayed according to the method of Edwards et al.,“Osteoinduction of Human Demineralized Bone: Characterization in a RatModel,” Clinical Orthopaedics & Rel. Res., 357:219-228, December 1998,incorporated herein by reference.

Superficially demineralized, as used herein, refers to bone-derivedelements possessing at least about 90 weight percent of their originalinorganic mineral content. In some embodiments, superficiallydemineralized contains at least about 90, 91, 92, 93, 94, 95, 96, 97, 98and/or 99 weight percent of their original inorganic material. Theexpression “partially demineralized” as used herein refers tobone-derived elements possessing from about 8 to about 90 weight percentof their original inorganic mineral content. In some embodiments,partially demineralized contains about 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34,35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88,89 and/or 90 weight percent of their original inorganic mineral content.The expression “fully demineralized” as used herein refers to bonecontaining less than 8% of its original mineral context. In someembodiments, fully mineralized contains about less than 8, 7, 6, 5, 4,3, 2 and/or 1% of its original mineral content.

The expression “average length to average thickness ratio” as applied tothe DBM fibers of the present application means the ratio of the longestaverage dimension of the fiber (average length) to its shortest averagedimension (average thickness). This is also referred to as the “aspectratio” of the fiber.

Fibrous, as used herein, refers to bone elements whose average length toaverage thickness ratio or aspect ratio of the fiber is from about 50:1to about 1000:1. In some embodiments, average length to averagethickness ratio or aspect ratio of the fiber is from about 50:1, 75:1,100:1, 125:1, 150:1, 175:1, 200:1, 225:1, 250:1, 275:1, 300:1, 325:1,350:1, 375:1, 400:1, 425:1, 450:1, 475:1, 500:1, 525:1, 550:1, 575:1,600:1, 625:1, 650:1, 675:1, 700:1, 725:1, 750:1, 775:1, 800:1, 825:1,850:1, 875:1, 900:1, 925:1, 950:1, 975:1 and/or 1000:1. In overallappearance the fibrous bone elements can be described as bone fibers,threads, narrow strips, or thin sheets. Often, where thin sheets areproduced, their edges tend to curl up toward each other. The fibrousbone elements can be substantially linear in appearance or they can becoiled to resemble springs. In some embodiments, the bone fibers are ofirregular shapes including, for example, linear, serpentine or curvedshapes. The bone fibers are preferably demineralized however some of theoriginal mineral content may be retained when desirable for a particularembodiment. In various embodiments, the bone fibers are mineralized. Insome embodiments, the fibers are a combination of demineralized andmineralized.

Non-fibrous, as used herein, refers to elements that have an averagewidth substantially larger than the average thickness of the fibrousbone element or aspect ratio of less than from about 50:1 to about1000:1. Preferably the non-fibrous bone elements are shaped in asubstantially regular manner or specific configuration, for example,triangular prism, sphere, cube, cylinder and other regular shapes. Bycontrast, particles such as chips, shards, or powders possess irregularor random geometries. It should be understood that some variation indimension will occur in the production of the elements of thisapplication and elements demonstrating such variability in dimension arewithin the scope of this application and are intended to be understoodherein as being within the boundaries established by the expressions“mostly irregular” and “mostly regular”.

The bone implant devices and methods according to the presentapplication increase DBM content in the device, increase the surfacearea of the DMB, and uniformly distribute the DBM throughout thedelivery device to enhance bone growth when the delivery device isimplanted at a bone defect. The bone implant devices and methodsprovided enhance bone growth by reducing the gaps that may exist betweenthe DBM particles and reduce the distance for cells (e.g., osteoclasts,osteoblasts, etc.) to travel throughout the device to allow those cellsto receive an adequate osteoinductive signal as opposed to only alongthe surface of the device. In some embodiment, the device improves thefusion of adjacent interspinous processes.

According to one aspect, there is a bone graft delivery devicecomprising: a porous biodegradable graft body for inducing bone growthat a surgical site, the porous biodegradable graft body havingdemineralized bone matrix (DBM) fibers disposed within the porousbiodegradable body, and DBM powder disposed adjacent to, on or in theDBM fibers, wherein the porous biodegradable graft body facilitatestransfer of cells into and out of the porous biodegradable graft body toinduce bone growth at the surgical site.

3D Printer Device

Provided are 3D printing devices and methods of use for creating hollowstructures such as mesh bags. Also provided are 3D printing devicesincluding a rotatable printing surface to create such hollow structures.Further provided are devices and methods for 3D printing onto such arotatable printing surface by continuous extrusion instead of stratifiedlayers. Additionally, provided are devices and methods for creatingstructures having a meshed design that are strong, flexible, stretchableand biocompatible.

Turning now to FIGS. 1-7, provided is a 3D printing device 10 forfabricating hollow structures, such as, mesh bags 70. 3D printing istypically done in 2 dimensions, one layer at a time. Material is laidout on a flat surface and the three dimensional structures are built upone layer at a time, usually through a melting or sintering process. Insome embodiments, a 3D printer having a rotatable printing surface isprovided to allow printing hollow structures, such as, for example, meshbags. In some embodiments, a print head applies material to the printsurface through continuous extrusion, instead of stratified layers, asis done by traditional 3D printing devices. In some embodiments, theprovided 3D printing device creates stronger structures and generatesless waste than traditional 3D printing devices.

As shown in FIG. 1, provided is a 3D printing device 10 for use in thefabrication of mesh bags 70. 3D printing device 10 includes a table 14having a base 16 and a printing surface 12. In some embodiments,printing surface 12 is mounted to printing table 14 including a base 16.Base 16 is configured for planar movement. In some embodiments, base 16is movable in the x-y plane and is laterally movable in both the x axisand the y axis for precise positioning of printing surface 12. Printingsurface 12, in some embodiments, is fixedly disposed with table 14 suchthat lateral movement of base 16 causes lateral movement of printingsurface 12. Movement of base 16 allows for positioning of printingsurface 12 relative to print head 30 to facilitate depositing materialsonto printing surface 12, as discussed herein.

Printing surface 12 is rotatable about an axis of rotation, as shown inFIGS. 2 and 3. In some embodiments, rotating printing surface 12includes a cylindrical shape extending along a longitudinal axis, asshown in FIG. 2. This allows printing of a round or circular implantwith a hollow region as the implant takes on the shape of the printsurface. In some embodiments, the printing surface includes othercross-sectional shapes, such as, for example, rectangular, oval,polygonal, irregular, undulating, or lobed. For example, as shown inFIG. 3, printing surface 12 may have a rectangular cross-sectionextending along a longitudinal axis. This allows printing of a square orrectangular implant, as the print surface rotates, the implant will takethe shape of the print surface. In alternative embodiments, printingsurface 12 includes a uniform diameter and/or cross-section along itsentire length. In other embodiments, printing surface 12 includes achanging diameter or cross-section along its length. For example, insome embodiments the diameter may increase from one end of printingsurface 12 to the other. In some embodiments, the cross section ofprinting surface 12 changes from one end to the other. For example, oneend of printing surface 12 may have a circular cross-section while theopposite end may have a rectangular cross-section. The size and shape ofprinting surface 12 may be changed according to the specifications andneeds of a particular medical procedure. In some embodiments, meshes areprinted onto the printing surface into which another object, such as forexample, bone material (e.g. surface demineralized bone chips and fullydemineralized bone fibers), can be placed inside the hollow region. Theshape of printing surface 12 defines the shape of the hollow structurecreated. As shown in FIG. 2, the shape of the mesh bag 70 created iscylindrical. As shown in FIG. 4, the shape of the mesh bag 70 created isthat of a hollowed out rectangular prism.

Printing surface 12 is rotatable about a rotation of axis defined byextension shaft 20, as discussed herein. In various embodiments,printing surface 12 is rotatable in either clockwise or counterclockwisedirections. In various embodiments, printing surface 12 is rotatable inboth clockwise and counterclockwise directions, as shown by arrow B inFIGS. 2 and 3. Printing surface 12 is configured to change direction ofrotation multiple times throughout the course of fabrication of a hollowstructure, such as, for example, mesh bag 70, as discussed herein. Forexample, the printing surface can rotate along a rotational axis 360degrees clockwise and/or counterclockwise to print the implant.

In some embodiments, printing surface 12 is movable between an expandedconfiguration and a collapsed configuration. In some embodiments,material 40 (which can be a biodegradable polymer) is deposited ontoprinting surface 12 while in the expanded configuration, and printingsurface 12 is moved to the collapsed configuration to remove the printedhollow structure. The print head 30 can contact the print surface 12 orthere can be a gap between the print surface and the print head so thatthe material can be printed on the print surface.

In some embodiments, printing surface 12 is fixedly disposed with table14 via a mounting bracket 18. The mounting bracket 18 may includecovering 15 for protection. In some embodiments, mounting bracket 18includes a motor to provide a rotational force to move printing surface12. In some embodiments, mounting bracket 18 is connected to extensionshaft 20. Printing surface 12 is connected to extension shaft 20 at afirst end of printing surface 12. Extension shaft 20 defines an axis ofrotation for printing surface 12 and is connected to mounting bracket 18via collet 22. In some embodiments, collet 22 is expandable to loosenthe grip on extension shaft 20. This allows extension shaft 20 andprinting surface 12 to be changed out for another printing surface 12which may be sized and/or shaped differently to cater to the needs of aparticular procedure.

In some embodiments, the 3D printing device further includes a printhead 30, such as, for example, an applicator that is movable in adirection transverse to the plane of movement for the base. In someembodiments, print head 30 is movable in the z axis, as shown by arrow Ain FIG. 1, to allow for different size fixtures, variable surfacestructures and to control the thickness of the extruded layer. Thus,print head 30 is movable to have an adjustable distance from printingsurface 12. Additionally, print head 30 is movable to accommodateprinting surfaces having various diameters or printing surfaces havinggradient diameters. In some embodiments, print head 30 is also movablein the x and y planes parallel with the plane of movement for the base.Thus, in some embodiments, print head 30 is movable in an oppositedirection from the movement of printing surface 12 to facilitate fasterprinting. In some embodiments, print head 30 is suspended from track 35.Track 35 provides a base of support for print head 30. In someembodiments, track 35 provides a predefined route of allowable movementfor print head 30 in directions shown as C. In some embodiments, track35 is hollow to allow flow of material 40 to be delivered to printingsurface 12, as described herein.

In some embodiments, printing surface 12 is treated with an adhesivematerial. The adhesive material may be textured or coated onto printingsurface 12. The adhesive may be heat sensitive or heat activated suchthat printing surface 12 becomes adhesive to material 40 when printingsurface 12 is heated, as discussed herein. An adhesive coating aids inpreventing printed material 40 from falling off printing surface 12during rotation. In some embodiments, the adhesive is deactivatedthrough cooling. In some embodiments, the adhesive may be removed byplacing printing surface in a solvent to dissolve the adhesive material.Once the adhesive material is removed, a hollow structure printed toprinting surface 12 may be removed.

As shown in FIG. 6, print head 30 includes a distal opening 32 throughwhich material 40 is deposited on printing surface 12. A tube portion 31of print head 30 includes a first diameter and extends distally to ahead portion 33 having a second diameter. In some embodiments, thesecond diameter is smaller than the first diameter. In variousembodiments, material 40 includes a biodegradable polymer. In someembodiments, material 40 comprises a bioerodible, a bioabsorbable,and/or a biodegradable biopolymer. Examples of suitable sustainedrelease biopolymers include but are not limited to poly (alpha-hydroxyacids), poly (lactide-co-glycolide) (PLGA), polylactide (PLA),polyglycolide (PG), polyethylene glycol (PEG) conjugates of poly(alpha-hydroxy acids), poly(orthoester)s (POE), polyaspirins,polyphosphagenes, collagen, starch, pre-gelatinized starch, hyaluronicacid, chitosans, gelatin, alginates, albumin, fibrin, vitamin Ecompounds, such as alpha tocopheryl acetate, d-alpha tocopherylsuccinate, D,L-lactide, or L-lactide, caprolactone, dextrans,vinylpyrrolidone, polyvinyl alcohol (PVA), PVA-g-PLGA, PEGT-PBTcopolymer (polyactive), PEO-PPO-PAA copolymers, PLGA-PEO-PLGA, PEG-PLG,PLA-PLGA, poloxamer 407, PEG-PLGA-PEG triblock copolymers, SAIB (sucroseacetate isobutyrate) or combinations thereof. In various embodiments,material 40 comprises poly(lactide-co-glycolide) (PLGA), polylactide(PLA), polyglycolide (PGA), D-lactide, D,L-lactide, L-lactide,D,L-lactide-co-ε-caprolactone,D,L-lactide-co-glycolide-co-ε-caprolactone, L-lactide-co-ε-caprolactoneor a combination thereof.

Print head 30 includes an inner lumen 34 and a central feed shaft 36.Feed shaft is configured to turn feed threads 38 to feed material 40from the proximal end of print head 30 through opening 32. Material 40is maintained in an external reservoir (not shown) and fed into lumen34. In some embodiments, material 40 is driven into lumen 34 by gravity.In some embodiments material 40 is drawn into lumen 34 by turning feedshaft 36 and feed threads 38. In some embodiments, 3D printing deviceincludes multiple print heads 30, each configured to deposit material 40onto printing surface 12.

In some embodiments, 3D printing device 10 further includes atemperature control unit 50 such as for example a heating or coolingunit connected to the printing surface. In some embodiments, temperaturecontrol unit 50 includes a heating unit. In other embodiments,temperature control unit 50 includes a cooling unit. In someembodiments, temperature control unit 50 is used to heat printingsurface 12 through electric heating elements underneath the surface ofprinting surface 12. Sufficient energy may be supplied through suchelectric conduits to provide a temperature on the surface of printingsurface 12 to melt and bond material 40 applied from print head 40. Insuch an embodiment, conduits 52 are electric heating conduits. In someembodiments, where material 40 comprises a highly viscous material, aheated printing surface 12 allows the material 40 to flow. In otherembodiments, the material is heated or cooled in reservoir 37 to allowthe desired flowability or viscosity of the material to make theimplant.

In some embodiments, the temperature control unit comprises a coolingunit. The cooling unit is used to cool printing surface 12 throughrefrigerant supply and return lines underneath printing surface 12. Insuch an embodiment, the supply and return lines are conduits 52. Theconduits 52 supply cooling fluid to printing surface 12 to cool andsolidify hot material 40 extruded onto the surface. In alternativeembodiments, reservoir 37 can have the cooling and heating unit to allowcooling or heating of the material.

In some embodiments, 3D printing device 10 includes a radiation sourceconfigured to supply and transfer energy to at least a portion of thepowder applied to the surface. In some embodiments, the radiation sourceis a laser positioned adjacent the print head. Laser 60 articulatingsuch that the supplied beam can be focused on selected portions ofprinting surface 12. Laser 60 is configured to be used during or afterprint head 30 deposits material 40 onto printing surface 12. The beam oflaser 60 is focused onto portions of material 40 on printing surface 12to melt or sinter the material as desired. Once the printed hollowstructure is complete, it may be removed from the residual powderedmaterial 40 left on printing surface 12, or the residual powderedmaterial 40 is brushed away. In some embodiments, the laser is focusedat a point adjacent opening 32 to sinter material as it is depositedonto printing surface 12. Such embodiments may facilitate theelimination of waste since the majority of material 40 extruded ontoprinting surface 12 is sintered.

In some embodiments, laser 60 may include any wavelength of visiblelight or UV light. In some embodiments, laser 60 emits alternative formsof radiation, such as, for example, microwave, ultrasound or radiofrequency radiation. In some embodiments, laser 60 is configured to befocused on a portion of printing surface 12 to sinter material 40deposited thereon. Laser 60 may be emitted in a beam having a smalldiameter. For example, the diameter of the beam may be between about0.01 mm and about 0.8 mm. In some embodiments, the diameter of the beammay be between about 0.1 mm and about 0.4 mm. In some embodiments, thediameter of the beam is adjustable to customize the intensity of thesintering. In some embodiments, the material is deposited on the printsurface 12 and the print head removes by, for example, heating thematerial to remove unwanted material from the print surface to make theimplant. The material remaining on the print surface after removal ofthe unwanted material will be the implant.

In some embodiments, 3D printing device 10 includes a controller orprocessor 102 to accept instructions and automatically manufacture ahollow structure, such as, for example, a mesh bag 70, based on theinstructions. In some embodiments, processor 102 comprises memory 100for temporary or permanent storage of instructions. Various instructionsmay be programmed and stored in the memory to make multiple designs ofmesh bags. In some embodiments, 3D printing device 10 includes an inputdevice 106, such as for example a keyboard to input commands andinstructions. In some embodiments, processor 102 of 3D printing device10 is configured to receive commands and instructions from an externalcomputer. For example, various instructions may be stored and executedlocally on an external computer to operate 3D printing device 10. Insome embodiments, the computer, 3D printing device can be one singledevice with component parts.

In some embodiments, processor 102 comprises logic to execute one ormore instructions to carry instructions of the computer system (e.g.,transmit instructions to the 3D printer, etc.). The logic for executinginstructions may be encoded in one or more tangible media for executionby the processor 102. For example, the processor 102 may execute codesstored in a computer-readable medium such as memory 100. Thecomputer-readable medium may be stored in, for example, electronic(e.g., RAM (random access memory), ROM (read-only memory), EPROM(erasable programmable read-only memory)), magnetic, optical (e.g., CD(compact disc), DVD (digital video disc)), electromagnetic,semiconductor technology, or any other suitable medium.

In some embodiments, the instructions include dimensions of a mesh bagto be made. For example, the instructions may include programming as tothe length and thickness of the mesh bag. Processor 102 carries out theinstructions by causing movement of base 16 relative to the print head30 while material 40 is applied to printing surface 12. Additionally,processor 102 may cause movement of print head 30 in a direction awayfrom printing surface 12 to allow for a thicker layer of material 40,according to the predetermined specifications in the instructions. Insome embodiments, processor 102 is configured to provide a single layerof material to make the mesh bag. The layer of material 40 depositedonto printing surface 12 may have uniform thicknesses or may includevaried thicknesses, such as thickness gradients across the length of themesh bag.

Once processor 102 receives the instructions, processor 102 directs the3D printing device to make the mesh bag based on the receivedinstructions. In some embodiments, processor 102 directs the lateralmovement of base 16 and printing surface 12, and the movement of printhead 30 transverse to base 16 and printing surface 12. In someembodiments, processor 102 also controls the direction of rotation, thedegree of rotation and the speed of rotation of printing surface 12. Insome embodiments, processor 102 moves, focuses and directs the radiationsource 60 to emit radiation at a predetermined point on printing surface12. In some embodiments, processor 102 directs the temperature controlunit to heat or cool printing surface 12. Based on the instructionsreceived, processor 102 coordinates simultaneous and/or ordered movementof base 16, printing surface 12, and print head 30 relative to oneanother. Processor 102 also controls the application of material 40 ontoprinting surface 12. For example, the processor 102 directs the pressureat which material 40 is released on to printing surface 12. Processor102 also directs the patterns of application onto printing surface 12,including portions where material 40 is not applied to printing surface12 to reduce waste. Processor 102 may also direct the radiation source60 to emit radiation, such as for example, focused beams of light, incontrolled pulses to sinter preselected portions of material 40 onprinting surface 12.

In some embodiments, processor 102 directs motors which control themovement and rotation of at least base 16, printing surface 12, andprint head 30 relative to one another. In some embodiments, processor102 directs coarse and/or fine movement of components of 3D printingdevice 10.

Although the components of the system of FIG. 8 are shown as separate,they may combined in one or more computer systems. Indeed, they may beone or more hardware, software, or hybrid components residing in (ordistributed among) one or more local or remote computer systems. It alsoshould be readily apparent that the components of the system asdescribed herein may be merely logical constructs or routines that areimplemented as physical components combined or further separated into avariety of different components, sharing different resources (includingprocessing units, memory, clock devices, software routines, logiccommands, etc.) as required for the particular implementation of theembodiments disclosed. Indeed, even a single general purpose computer(or other processor-controlled device) executing a program stored on anarticle of manufacture (e.g., recording medium or other memory units) toproduce the functionality referred to herein may be utilized toimplement the illustrated embodiments. It also will be understood thatthe plurality of computers or servers can be used to allow the system tobe a network based system having a plurality of computers linked to eachother over the network or Internet or the plurality of computers can beconnected to each other to transmit, edit, and receive data via cloudcomputers.

The computer (e.g., memory, processor, storage component, etc.) may beaccessed by authorized users. Authorized users may include at least oneengineer, technician, surgeon, physician, nurse, and/or health careprovider, manufacturer, etc.).

The user can interface with the computer via a user interface that mayinclude one or more display devices 104 (e.g., CRT, LCD, or other knowndisplays) or other output devices (e.g., printer, etc.), and one or moreinput devices (e.g., keyboard, mouse, stylus, touch screen interface, orother known input mechanisms) for facilitating interaction of a userwith the system via user interface. The user interface may be directlycoupled to database or directly coupled to a network server system viathe Internet or cloud computing. In accordance with one embodiment, oneor more user interfaces are provided as part of (or in conjunction with)the illustrated systems to permit users to interact with the systems.

The user interface device may be implemented as a graphical userinterface (GUI) containing a display 104 or the like, or may be a linkto other user input/output devices known in the art. Individual ones ofa plurality of devices (e.g., network/stand-alone computers, personaldigital assistants (PDAs), WebTV (or other Internet-only) terminals,set-top boxes, cellular/phones, screenphones, pagers, blackberry, smartphones, iPhone, iPad, table, peer/non-peer technologies, kiosks, orother known (wired or wireless) communication devices, etc.) maysimilarly be used to execute one or more computer programs (e.g.,universal Internet browser programs, dedicated interface programs, etc.)to allow users to interface with the systems in the manner described.Database hardware and software can be developed for access by usersthrough personal computers, mainframes, and other processor-baseddevices. Users may access and data stored locally on hard drives,CD-ROMs, stored on network storage devices through a local area network,or stored on remote database systems through one or more disparatenetwork paths (e.g., the Internet).

The database can be stored in storage devices or systems (e.g., RandomAccess Memory (RAM), Read Only Memory (ROM), hard disk drive (HDD),floppy drive, zip drive, compact disk-ROM, DVD, bubble memory, flashdrive, redundant array of independent disks (RAID), network accessiblestorage (NAS) systems, storage area network (SAN) systems, etc.), CAS(content addressed storage) may also be one or more memory devicesembedded within a CPU, or shared with one or more of the othercomponents, and may be deployed locally or remotely relative to one ormore components interacting with the memory or one or more modules. Thedatabase may include data storage device, a collection component forcollecting information from users or other computers into centralizeddatabase, a tracking component for tracking information received andentered, a search component to search information in the database orother databases, a receiving component to receive a specific query froma user interface, and an accessing component to access centralizeddatabase. Receiving component is programmed for receiving a specificquery from one of a plurality of users. The database may also include aprocessing component for searching and processing received queriesagainst data storage device containing a variety of informationcollected by collection device.

The disclosed system may, in some embodiments, be a computer networkbased system. The computer network may take any wired/wireless form ofknown connective technology (e.g., corporate or individual LAN,enterprise WAN, intranet, Internet, Virtual Private Network (VPN),combinations of network systems, etc.) to allow a server to providelocal/remote information and control data to/from other locations (e.g.,other remote database servers, remote databases, network servers/userinterfaces, etc.). In accordance with one embodiment, a network servermay be serving one or more users over a collection of remote anddisparate networks (e.g., Internet, intranet, VPN, cable, specialhigh-speed ISDN lines, etc.). The network may comprise one or moreinterfaces (e.g., cards, adapters, ports) for receiving data,transmitting data to other network devices, and forwarding received datato internal components of the system (e.g., 3D printers, printer heads,etc.).

In accordance with one embodiment of the present application, the datamay be downloaded in one or more textual/graphical formats (e.g., RTF,PDF, TIFF, JPEG, STL, XML, XDFL, TXT etc.), or set for alternativedelivery to one or more specified locations (e.g., via e-mail, fax,regular mail, courier, etc.) in any desired format (e.g., print, storageon electronic media and/or computer readable storage media such asCD-ROM, etc.). The user may view viewing the search results andunderlying documents at the user interface, which allows viewing of oneor more documents on the same display 104.

Mesh Formulations

In some embodiments, mesh bags 70 are formed from material 40 extrudedfrom print head 30. Mesh bags 70 comprise a system of threads 72 whichare extruded directly onto printing surface 12. Threads 72 may beextruded in various patterns, and may be sized according to therequirements of a particular application. For example, threads 72 may beextruded from print head 30 in a weave pattern in which threads 72 areinterwoven with one another such that each thread 72 alternatinglyinterlaces above and below adjacent threads 72. In other embodiments,threads 72 may be extruded in other ways. For example, horizontal rowsof threads 72 may be extruded in a first step, and in a second stepvertical rows of threads 72 may be extruded on top of the horizontalrows. A radiation source, such as laser 60 may be configured to sinterthe extruded rows together to form a mesh bag 70.

In some embodiments as shown in FIG. 5A, a completely printed mesh bag70 is formed having a continuous surface 75 formed from threads 72. Meshbag 70 includes oppositely positioned ends 77, 79. There is no seal atthese ends as the bag was 3D printed allowing for continuousmanufacture. Mesh bags that are not manufactured by 3D printing wouldhave seals on three of the four corners of the bag. In the 3D printedmesh bag of the current application, the bottom end 73 of the mesh bagis the only one sealed so that contents do not fall out. In someembodiments, end 71 is open to allow placement of bone material in thehollow region 81 of the mesh bag. Opening 71 allows entrance into thehollow region 81 of the mesh bag, where bone material is placed insideof it, the implant is then placed at a bone defect and the mesh bagallows the osteoinductive factors to leave the mesh bag and allowsinflux of bone cells into the mesh bag. The mesh bag is porous so as toallow influx and efflux of material.

In FIG. 5B, the hollow region 81 of the implant is shown below opening71 of the mesh bag. The mesh bag is filled with bone particles 83 (e.g.,surface demineralized chips and fully demineralized fibers) to enhancebone growth.

In some embodiments, the dimensions of the print surface 12 allows forprinting a mesh bag 70 of different dimensions and shapes thatcorrespond to the print surface 12 (e.g., circular, rectangular, square,etc.) The rotation of the print surface shown as B allows the implant(e.g., mesh bag 70) to be printed continuously so that there is areduced need for sealing the hollow region of the implant.

In some embodiments, mesh bag 70 includes a flexibility as to be flatpackable and extends between oppositely positioned ends 77 and 79. Insome embodiments, mesh bag 70 forms a cylindrical shape betweenoppositely positioned ends 77 and 79.

The threads 72 may be configured to allow ingrowth of cells while alsoretaining the osteogenic material within the compartment of mesh bag 70.In some embodiments, print head 30 is configured to extrude threads 72having a predetermined thickness. In some embodiments, strands 72 have athickness of about 0.01 mm to about 2.0 mm. In some embodiments, strands72 have a thickness of about 0.05 mm to about 1.0 mm, or about 0.1 toabout 0.5 mm. The thickness of strands 72 may be uniform along thelength of each strand, or varied across the length of each strand. Insome embodiments, some strands 72 have a greater thickness than otherstrands 72 in a mesh bag 70. Strands 72 may be sized to allow forcustomizable pore sizes between strands 72. In some embodiments, theporous mesh bag 70 is configured to facilitate transfer of substancesand/or materials surrounding the surgical site. Upon implantation to asurgical site, mesh bag 70 may participate in, control, or otherwiseadjust, or penetration of the mesh bag by surrounding materials, such ascells or tissue.

In various embodiments, mesh bag 70 may be sized according to the needsof a particular application. For example, mesh bag 70 may includedimensions between about 1 mm to about 100 mm in diameter. In someembodiments, mesh bag 70 includes a diameter of about 5 mm, 10 mm, 15mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, or 100 mm. In someembodiments, mesh bag 70 includes a length between about 0.1 cm to about10 cm. In some embodiments, mesh bag 70 includes a length of about 1 cm,2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, or 10 cm.

In some embodiments, strands 72 are extruded onto printing surface 12 ina wave-like configuration having alternating peaks and crests. In someembodiments, printing surface 12 is rotated in alternating clockwise andcounterclockwise directions while material 40 is extruded onto thesurface to create sinusoidal shaped waves having evenly shaped curves onthe peaks and crests. In some embodiments, the peaks and crests of thewaves are pointed to impart variable characteristics to mesh bag 70. Insome embodiments, strands 72 are extruded adjacent to one another suchthat the peaks of a first strand 72 is extruded to contact the crest ofan adjacent second strand 72. In some embodiments, the mesh bag may becreated entirely from strands 72 having this configuration. Wave-shapedstrands 72 impart flexibility and stretchable characteristics onto themanufactured mesh bag 70. The wavelength of the wave-shaped strands 72may be altered to customize stretchability of mesh bag 70. For example,strands 72 having shorter wavelengths will be able to be stretched morethan strands 72 having longer wavelengths. In some embodiments, thestretchability of mesh bag 70 is uniform across its length. In someembodiments, mesh bag 70 includes regions of increased stretchabilityaccording to the needs of a surgical application.

The shape, mesh size, thickness, and other structural characteristics,of the mesh bags e.g., architecture, may be customized for the desiredapplication. For example, to optimize cell or fluid migration throughthe mesh, the pore size may be optimized for the viscosity and surfacetension of the fluid or the size of the cells. For example, pore sizesbetween strands 72 on the order of approximately 100-200 μm may be usedif cells are to migrate through the mesh. In other embodiments, thewave-shaped strands 72 may be extruded to have larger peaks and crestsand the size of the pores may be larger. For example, in someembodiments, the pore size between strands 72 may be about 0.1 mm toabout 5 mm, about 0.5 mm to about 3 mm, or about 1 mm to about 2 mm.Mesh size may be controlled by physically weaving strands and bycontrolling the thickness of strands 72 extruded and sintered onprinting surface 12.

In various embodiments, the mesh bag made by 3D printing device 10 mayhave varying degrees of permeability across its surface. It may bepermeable, semi-permeable, or non-permeable. Permeability may be withrespect to cells, to liquids, to proteins, to growth factors, to bonemorphogenetic proteins, or other. In further embodiments, the materialmay be braided.

The mesh bag may have any suitable configuration. For example, the meshbag may be printed onto a printing surface 12 having a variety ofshapes, such as, for example, a ring, a cylinder, a cage, a rectangularshape, a suture-like wrap, a continuous tube, or other configurations.Printing surface 12 provides a scaffold onto which mesh bag 70 isprinted and from which mesh bag 70 derives its shape. In specificembodiments, the mesh bag may be formed as a thin tube designed to beinserted through catheters or an introducer tube, a rectangular shapedesigned to fit adjacent to spinal processes for posterolateral spinefusion, a cube like structure, as shown in FIG. 4, designed to fitbetween vertebral bodies or within cages for interbody spinal fusion, atube-like shape, relatively flat shapes, rectangular shapes, structurespreshaped to fit around various implants (e.g. dental, doughnut withhole for dental implants), or relatively elastic ring-like structuresthat will stretch and then conform to shapes (e.g. rubber band fittedaround processes). In an embodiment wherein the mesh bag is formed as acage, the cage may comprise a plurality of crossed fibers 72, whichdefine between them a series of openings for tissue ingrowth. Any ofthese shapes may be used to contain osteogenic material such as bonematerial, as discussed herein. Mesh bags 70 may be printed and sinteredonto printing surface 12 in such a way as to have one open end, as shownin FIG. 5. In other embodiments, mesh bag 70 may be printed and sinteredonto printing surface 12 to have two open ends. At least one end is leftopen to allow mesh bag 70 to be loaded with an osteogenic material, suchas bone material, as discussed herein. In various embodiments, mesh bag70 is sealed at one or both ends prior to implantation at a surgicalsite. In various embodiments, the mesh sealed bag is sealed via heatsealing, stitching, adhesion, tying, fold lock and cinching.

In various embodiments, the manufactured mesh bags 70 may be formedhaving one or more opened ends to facilitate infusion with bonematerial. Additionally, the flexible character of the mesh materialallows for the mesh bag 70 to be manipulated into a plurality ofcompartments. For example, in a tubular embodiment, the tube may beformed into a plurality of compartments by tying a cord around the tubeat one or more points, or by other suitable mechanism such as crimping,twisting, knotting, stapling, or sewing.

A suitable mesh bag that can be made by the 3D printing device of thecurrent application is MAGNIFUSE® Bone Graft, available from Medtronic,which comprises surface demineralized bone chips mixed withnon-demineralized cortical bone fibers or fully demineralized bonefibers sealed in an absorbable PGA mesh bag or pouch.

In certain embodiments, a bone void can be filled by mesh bag 70containing bone material. A compartment within mesh bag 70 can be atleast partially filled with a bone repair substance. In variousembodiments, at least partially filled as used herein, can mean that apercentage of the volume of a compartment or hollow region is at least70% occupied, at least 75% occupied, at least 80% occupied, at least 85%occupied, at least 90% occupied, at least 95% occupied, or 100%occupied. Mesh bag 70 can be inserted into an opening in the defectuntil the defect is substantially filled. In various embodiments, asubstantially filled as used herein can mean that a percentage of thevolume of a defect is at least 70% occupied, at least 75% occupied, atleast 80% occupied, at least 85% occupied, at least 90% occupied, atleast 95% occupied, or 100% occupied. The excess material extendingbeyond the surface of the bone if the bone were without the defect canthen be removed, or at least partially removed such that the opening ofthe defect is flush with the uninjured bone surface.

In some embodiments, mesh bag 70 may be labeled. Such labeling may bedone in any suitable manner and at any suitable location on mesh bag 70.In some embodiments, labeling may be done by using a silk screenprinting, using an altered weaving or knotting pattern, by usingdifferent colored threads 72, or other. The labeling may indicateinformation regarding mesh bag 70. Such information might include partnumber, donor id number, number, lettering or wording indicating orderof use in the procedure or implant size, etc.

In one embodiment, mesh bag 70 may comprise a penetrable material at afirst compartment configured for placement adjacent bone and asubstantially impenetrable material at a second compartment configuredfor placement adjacent soft tissue. For example, the pore size betweenstrands 72 at a first region of mesh bag 70 may be sized large enough toallow cell migration through mesh bag 70, but the pore size betweenstrands 72 at a second region of mesh bag 70 may be sized small enough(or may include a lack of pores altogether) to prevent cell migration.Alternatively, the material of the mesh bag 70 may have a uniformconfiguration such that adjacent compartments may have substantiallyidentical characteristics. By way of example only, mesh bag 70 may havea porous surface that is positioned adjacent bone, and a separate oropposite surface that has a generally impenetrable surface that ispositioned adjacent soft tissue. Alternatively, mesh bag 70 may have onecompartment that comprises a porous material, and a second compartmentthat comprises a substantially impenetrable material.

For both single and multi-compartment mesh bags 70, the mesh bag 70 maybe closed after filling substances. Accordingly, mesh bag 70 may beprovided in an unfilled, unsealed state immediately followingfabrication with 3D printing device 10. After a substance for deliveryis placed in mesh bag 70, mesh bag 70 may be permanently or temporarilyclosed. Permanent closure may be, for example, by heat sealing,stitching, adhesion, or other methods. Temporary closure may be bytying, fold lock, cinching, or other means. A temporarily closed meshbag 70 can be opened without damaging the mesh bag during surgicalimplantation to add or remove substances in the mesh bag.

Suitable adhesives for use may include, for example, cyanoacrylates(such as histoacryl, B Braun, which is n-Butyl-2 Cyanoacrylate; orDermabond, which is 2-octylcyanoacrylate); epoxy-based compounds, dentalresin sealants, dental resin cements, glass ionomer cements, polymethylmethacrylate, gelatin-resorcinol-formaldehyde glues, collagen-basedglues, inorganic bonding agents such as zinc phosphate, magnesiumphosphate or other phosphate-based cements, zinc carboxylate, L-DOPA(3,4-dihydroxy-L-phenylalanine), proteins, carbohydrates, glycoproteins,mucopolysaccharides, other polysaccharides, hydrogels, protein-basedbinders such as fibrin glues and mussel-derived adhesive proteins, andany other suitable substance. Adhesives may be selected for use based ontheir bonding time; e.g., in some circumstances, a temporary adhesivemay be desirable, e.g., for fixation during the surgical procedure andfor a limited time thereafter, while in other circumstances a permanentadhesive may be desired. Where the compartment is made of a materialthat is resorbable, the adhesive can be selected that would adhere forabout as long as the material is present in the body.

In some embodiments, biological attachment may be via mechanisms thatpromote tissue ingrowth such as by a porous coating or ahydroxyapatite-tricalcium phosphate (HA/TCP) coating. Generally,hydroxyapatite bonds by biological effects of new tissue formation.Porous ingrowth surfaces, such as titanium alloy materials in a beadedcoating or tantalum porous metal or trabecular metal may be used andfacilitate attachment at least by encouraging bone to grow through theporous implant surface. These mechanisms may be referred to asbiological attachment mechanisms.

In some embodiments, mesh bag 70 comprises an extruded material 40arranged in a mesh configuration. In some embodiments, material 40 ofmesh bag 70 is biodegradable. In some embodiments, mesh bag 70 includesonly one material which is uniformly extruded to form the entirety ofmesh bag 70. In some embodiments, mesh bag 70 comprises a blend ofsuitable materials 40. In some embodiments, a first group of strands 72may comprise a first material 40 and a second group of strands 72comprises a second material 40. In some embodiments, print head 30 isconfigured to extrude more than one type of material 40. In someembodiments, a first print head 30 is configured to extrude a firstmaterial 40 to form threads 72 and a second print head 30 is configuredto extrude a second material 40 to form threads 72.

In some embodiments, suitable materials include natural materials,synthetic polymeric resorbable materials, synthetic polymericnon-resorbable materials, and other materials. Natural mesh materialsinclude silk, extracellular matrix (such as DBM, collagen, ligament,tendon tissue, or other), silk-elastin, elastin, collagen, andcellulose. Synthetic polymeric resorbable materials include poly(lacticacid) (PLA), poly(glycolic acid) (PGA), poly(lactic acid-glycolic acid)(PLGA), polydioxanone, PVA, polyurethanes, polycarbonates, and others.

In some embodiments, the material of mesh bag 70 comprises a polymermatrix. In some embodiments, DBM fibers and/or DBM powder are suspendedin the polymer matrix to facilitate transfer of cells into and out ofthe mesh bag to induce bone growth at the surgical site. In variousembodiments, mesh bag 70 further comprises mineralized bone fiberssuspended in the polymer matrix. In some embodiments, the DBM powder issuspended in the polymer matrix between the DBM fibers and themineralized bone fibers. In some embodiments, the DBM powder issuspended between the DBM fibers in the polymer matrix so as to reduceand/or eliminate gaps that exist between the fibers. In someembodiments, the DBM powder is suspended between the DBM fibers in thepolymer matrix to improve osteoinductivity for facilitating bone fusion,for example, interspinous process fusion.

In some embodiments, the polymer matrix comprises a bioerodible, abioabsorbable, and/or a biodegradable biopolymer that may provideimmediate release, or sustained release. Examples of suitable sustainedrelease biopolymers include but are not limited to poly (alpha-hydroxyacids), poly (lactide-co-glycolide) (PLGA), polylactide (PLA),polyglycolide (PG), polyethylene glycol (PEG) conjugates of poly(alpha-hydroxy acids), poly(orthoester)s (POE), polyaspirins,polyphosphagenes, collagen, starch, pre-gelatinized starch, hyaluronicacid, chitosans, gelatin, alginates, albumin, fibrin, vitamin Ecompounds, such as alpha tocopheryl acetate, d-alpha tocopherylsuccinate, D,L-lactide, or L-lactide, caprolactone, dextrans,vinylpyrrolidone, polyvinyl alcohol (PVA), PVA-g-PLGA, PEGT-PBTcopolymer (polyactive), PEO-PPO-PAA copolymers, PLGA-PEO-PLGA, PEG-PLG,PLA-PLGA, poloxamer 407, PEG-PLGA-PEG triblock copolymers, SAIB (sucroseacetate isobutyrate) or combinations thereof. As persons of ordinaryskill are aware, mPEG and/or PEG may be used as a plasticizer for PLGA,but other polymers/excipients may be used to achieve the same effect.mPEG imparts malleability to the polymer. In some embodiments, thesebiopolymers may also be coated on mesh bag 70 to provide a desiredrelease profile or ingrowth of tissue. In some embodiments, the coatingthickness may be thin, for example, from about 5, 10, 15, 20, 25, 30,35, 40, 45 or 50 microns to thicker coatings 60, 65, 70, 75, 80, 85, 90,95, 100 microns to delay release of the substance from the medicaldevice. In some embodiments, the range of the coating on the mesh bagranges from about 5 microns to about 250 microns or 5 microns to about200 microns.

In various embodiments, various components of mesh bag 70 comprisespoly(lactide-co-glycolide) (PLGA), polylactide (PLA), polyglycolide(PGA), D-lactide, D,L-lactide, L-lactide, D,L-lactide-co-ε-caprolactone,D,L-lactide-co-glycolide-co-ε-caprolactone, L-lactide-co-ε-caprolactoneor a combination thereof.

In some embodiments, material 40 of mesh bag 70 further comprises bonemorphogenic proteins (BMPs), growth factors, antibiotics, angiogenesispromoting materials, bioactive agents or other actively releasingmaterials.

The mesh bag 70 may be used to deliver a substance comprising anysuitable biocompatible material. In specific embodiments, mesh bag 70may be used to deliver surface demineralized bone chips, optionally of apredetermined particle size, demineralized bone fibers, optionallypressed, and/or allograft. For embodiments wherein the substance isbiologic, the substance may be autogenic, allogenic, xenogenic, ortransgenic. Other suitable materials that may be positioned in mesh bag70 include, for example, protein, nucleic acid, carbohydrate, lipids,collagen, allograft bone, autograft bone, cartilage stimulatingsubstances, allograft cartilage, TCP, hydroxyapatite, calcium sulfate,polymer, nanofibrous polymers, growth factors, carriers for growthfactors, growth factor extracts of tissues, DBM, dentine, bone marrowaspirate, bone marrow aspirate combined with various osteoinductive orosteoconductive carriers, concentrates of lipid derived or marrowderived adult stem cells, umbilical cord derived stem cells, adult orembryonic stem cells combined with various osteoinductive orosteoconductive carriers, transfected cell lines, bone forming cellsderived from periosteum, combinations of bone stimulating and cartilagestimulating materials, committed or partially committed cells from theosteogenic or chondrogenic lineage, or combinations of any of the above.

In accordance with some embodiments, the material may be supplemented,further treated, or chemically modified with one or more bioactiveagents or bioactive compounds. Bioactive agent or bioactive compound, asused herein, refers to a compound or entity that alters, inhibits,activates, or otherwise affects biological or chemical events. Forexample, bioactive agents may include, but are not limited to,osteogenic or chondrogenic proteins or peptides; DBM powder; collagen,insoluble collagen derivatives, etc., and soluble solids and/or liquidsdissolved therein; anti-AIDS substances; anti-cancer substances;antimicrobials and/or antibiotics such as erythromycin, bacitracin,neomycin, penicillin, polymycin B, tetracyclines, biomycin,chloromycetin, and streptomycins, cefazolin, ampicillin, azactam,tobramycin, clindamycin and gentamycin, etc.; immunosuppressants;anti-viral substances such as substances effective against hepatitis;enzyme inhibitors; hormones; neurotoxins; opioids; hypnotics;anti-histamines; lubricants; tranquilizers; anti-convulsants; musclerelaxants and anti-Parkinson substances; anti-spasmodics and musclecontractants including channel blockers; miotics and anti-cholinergics;anti-glaucoma compounds; anti-parasite and/or anti-protozoal compounds;modulators of cell-extracellular matrix interactions including cellgrowth inhibitors and antiadhesion molecules; vasodilating agents;inhibitors of DNA, RNA, or protein synthesis; anti-hypertensives;analgesics; anti-pyretics; steroidal and non-steroidal anti-inflammatoryagents; anti-angiogenic factors; angiogenic factors and polymericcarriers containing such factors; anti-secretory factors; anticoagulantsand/or antithrombotic agents; local anesthetics; ophthalmics;prostaglandins; anti-depressants; anti-psychotic substances;anti-emetics; imaging agents; biocidal/biostatic sugars such as dextran,glucose, etc.; amino acids; peptides; vitamins; inorganic elements;co-factors for protein synthesis; endocrine tissue or tissue fragments;synthesizers; enzymes such as alkaline phosphatase, collagenase,peptidases, oxidases, etc.; polymer cell scaffolds with parenchymalcells; collagen lattices; antigenic agents; cytoskeletal agents;cartilage fragments; living cells such as chondrocytes, bone marrowcells, mesenchymal stem cells; natural extracts; genetically engineeredliving cells or otherwise modified living cells; expanded or culturedcells; DNA delivered by plasmid, viral vectors, or other member; tissuetransplants; autogenous tissues such as blood, serum, soft tissue, bonemarrow, etc.; bioadhesives; bone morphogenic proteins (BMPs);osteoinductive factor (IFO); fibronectin (FN); endothelial cell growthfactor (ECGF); vascular endothelial growth factor (VEGF); cementumattachment extracts (CAE); ketanserin; human growth hormone (HGH);animal growth hormones; epidermal growth factor (EGF); interleukins,e.g., interleukin-1 (IL-1), interleukin-2 (IL-2); human alpha thrombin;transforming growth factor (TGF-beta); insulin-like growth factors(IGF-1, IGF-2); parathyroid hormone (PTH); platelet derived growthfactors (PDGF); fibroblast growth factors (FGF, BFGF, etc.); periodontalligament chemotactic factor (PDLGF); enamel matrix proteins; growth anddifferentiation factors (GDF); hedgehog family of proteins; proteinreceptor molecules; small peptides derived from growth factors above;bone promoters; cytokines; somatotropin; bone digesters; antitumoragents; cellular attractants and attachment agents; immuno-suppressants;permeation enhancers, e.g., fatty acid esters such as laureate,myristate and stearate monoesters of polyethylene glycol, enaminederivatives, alpha-keto aldehydes, etc.; and nucleic acids.

In certain embodiments, the bioactive agent may be a drug. In someembodiments, the bioactive agent may be a growth factor, cytokine,extracellular matrix molecule, or a fragment or derivative thereof, forexample, a protein or peptide sequence such as RGD.

In some embodiments, the material may have a modulus of elasticity inthe range of about 1×10² to about 6×10⁵ dyn/cm², or 2×10⁴ to about 5×10⁵dyn/cm², or 5×10⁴ to about 5×10⁵ dyn/cm². After the device isadministered to the target site, the material may have a modulus ofelasticity in the range of about 1×−10² to about 6×10⁵ dynes/cm², or2×10⁴ to about 5×10⁵ dynes/cm², or 5×10⁴ to about 5×10⁵ dynes/cm².

The material may have functional characteristics. Alternatively, othermaterials having functional characteristics may be incorporated into themesh bag 70. Functional characteristics may include radiopacity,bacteriocidity, source for released materials, tackiness, etc. Suchcharacteristics may be imparted substantially throughout mesh bag 70 orat only certain positions or portions of mesh bag 70.

Suitable radiopaque materials include, for example, ceramics,mineralized bone, ceramics/calcium phosphates/calcium sulfates, metalparticles, fibers, and iodinated polymer (see, for example,WO/2007/143698). Polymeric materials may be used to form mesh bag 70 andbe made radiopaque by iodinating them, such as taught for example inU.S. Pat. No. 6,585,755, herein incorporated by reference in itsentirety. Other techniques for incorporating a biocompatible metal ormetal salt into a polymer to increase radiopacity of the polymer mayalso be used. Suitable bacteriocidal materials may include, for example,trace metallic elements. In some embodiments, trace metallic elementsmay also encourage bone growth.

In some embodiments, mesh bag 70 may comprise a material that becomestacky upon wetting. Such material may be, for example, a protein orgelatin based material. Tissue adhesives, including mussel adhesiveproteins and cryanocrylates, may be used to impart tackiness to mesh bag70. In further examples, alginate or chitosan material may be used toimpart tackiness to mesh bag 70. In further embodiments, an adhesivesubstance or material may be placed on a portion of mesh bag 70 or in aparticular region of mesh bag 70 to anchor that portion or region ofmesh bag 70 in place at an implant site.

Bone Material

In various embodiments, the mesh bags made by 3D printing device 10include compartments to hold osteogenic material, such as bone material.In various embodiments, the bone material may be particulated such as,for example, in bone powder or fiber form. If the bone is demineralized,the bone may be made into a particulate before, during or afterdemineralization. In some embodiments, the bone may be monolithic andmay not be a particulate.

The bone may be milled and ground or otherwise processed into particlesof an appropriate size before or after demineralization. The particlesmay be particulate (e.g., powder) or fibrous. The terms milling orgrinding are not intended to be limited to production of particles of aspecific type and may refer to production of particulate or fibrousparticles. In certain embodiments, the particle size may be greater than25 microns, such as ranging from about 25 to about 2000 microns, or fromabout 25 to about 500 microns or from about 200 to about 1000 microns.In some embodiments, the size of the bone powder particles are less than100 microns. In some embodiments, the size of the bone powder particlesare less than 500 microns.

In some embodiments, the particle size of the particles may be 25, 30,35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115,120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185,190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255,260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 315, 320, 325,330, 335, 340, 345, 350, 355, 360, 365, 370, 375, 380, 385, 390, 395,400, 405, 410, 415, 420, 425, 430, 435, 440, 445, 450, 455, 460, 465,470, 475, 480, 485, 490, 495, 500, 505, 510, 515, 520, 525, 530, 535,540, 545, 550, 555, 560, 565, 570, 575, 580, 585, 590, 595, 600, 605,610, 615, 620, 625, 630, 635, 640, 645, 650, 655, 660, 665, 670, 675,680, 685, 690, 695, 700, 705, 710, 715, 720, 725, 730, 735, 740, 745,750, 755, 760, 765, 770, 775, 780, 785, 790, 795, 800, 805, 810, 815,820, 825, 830, 835, 840, 845, 850, 855, 860, 865, 870, 875, 880, 885,890, 895, 900, 905, 910, 915, 920, 925, 930, 935, 940, 945, 950, 955,960, 965, 970, 975, 980, 985, 990, 995, 1000, 1005, 1010, 1015, 1020,1025, 1030, 1035, 1040, 1045, 1050, 1055, 1060, 1065, 1070, 1075, 1080,1085, 1090, 1095, 1100, 1105, 1110, 1115, 1120, 1125, 1130, 1135, 1140,1145, 1150, 1155, 1160, 1165, 1170, 1175, 1180, 1185, 1190, 1195, 1200,1205, 1210, 1215, 1220, 1225, 1230, 1235, 1240, 1245, 1250, 1255, 1260,1265, 1270, 1275, 1280, 1285, 1290, 1295, 1300, 1305, 1310, 1315, 1320,1325, 1330, 1335, 1340, 1345, 1350, 1355, 1360, 1365, 1370, 1375, 1380,1385, 1390, 1395, 1400, 1405, 1410, 1415, 1420, 1425, 1430, 1435, 1440,1445, 1450, 1455, 1460, 1465, 1470, 1475, 1480, 1485, 1490, 1495, 1500,1505, 1510, 1515, 1520, 1525, 1530, 1535, 1540, 1545, 1550, 1555, 1560,1565, 1570, 1575, 1580, 1585, 1590, 1595, 1600, 1605, 1610, 1615, 1620,1625, 1630, 1635, 1640, 1645, 1650, 1655, 1660, 1665, 1670, 1675, 1680,1685, 1690, 1695, 1700, 1705, 1710, 1715, 1720, 1725, 1730, 1735, 1740,1745, 1750, 1755, 1760, 1765, 1770, 1775, 1780, 1785, 1790, 1795, 1800,1805, 1810, 1815, 1820, 1825, 1830, 1835, 1840, 1845, 1850, 1855, 1860,1865, 1870, 1875, 1880, 1885, 1890, 1895, 1900, 1905, 1910, 1915, 1920,1925, 1930, 1935, 1940, 1945, 1950, 1955, 1960, 1965, 1970, 1975, 1980,1985, 1990, 1995 and/or 2000 microns. After grinding, the bone particlesmay be sieved to select those particles of a desired size. In certainembodiments, the particles may be sieved though a 25 micron sieve, a 50micron sieve, a 75 micron sieve, a 100 micron sieve, a 125 micron sieve,a 150 micron sieve, a 175 micron sieve and/or a 200 micron sieve.

In some embodiments, the bone powder comprises DBM and/or mineralizedbone. In some embodiments, the size of the bone powder particles is lessthan 25 microns. In some embodiments, the bone powder particle size isabout 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23 and/or 24 microns.

In various embodiments, the bone powder particles and/or the DBM and/ormineralized bone fibers have a sticky outer surface such that the bonepowder can adhere to DBM and/or mineralized bone fibers. In variousembodiments, the bone particles are naturally sticky. In someembodiments, an adhesive agent is applied to the bone powder and/or thebone fibers comprising a bio-adhesive, glue, cement, cyanoacrylate,silicones, hot melt adhesives and/or cellulosic binders. In variousembodiments, the adhesive may be applied to the surface of the bonepowder particles by spraying or brushing. In some embodiments, a chargeis applied to the fibers and an opposite charge is applied to the bonepowder, (i.e., the technique of electrostatic precipitation). The bonepowder will be attracted to, and tenaciously adhere to, the surface ofthe fiber. Any of these application techniques can be repeated one ormore times to build up a relatively thick layer of adherent bone powderon the surface of the fibers.

The bone powder can be applied directly to the DBM fiber and/or fullymineralized fiber and the mixture can be disposed in mesh bag 70. Insome embodiments, the bone material inserted into a mesh bag 70 containspores having a pore size from about 0.5 to about 2,000 microns. In someembodiments, bone material inserted into a mesh bag 70 contains poreshaving a pore size of from about 0.5, 5, 50, 100, 150, 200, 250, 300,350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1,000,1,050, 1,100, 1,1.50, 1,200, 1,250, 1,300, 1,350, 1,400, 1,450, 1,500,1,550 1,600, 1,650, 1,700, 1,750, 1,800 1,850 1,900, 1,950 to about2,000 microns. In some embodiments, the pore size of the bone materialis un In some embodiments, the pore size of bone material is non-uniformand includes various pore sizes in the range from 0.5 to about 2,000microns. Alternatively, the DBM fiber, and DBM powder can be placed in apolymer (e.g., collagen) and inserted into a porous biodegradable graftbody (e.g., a pouch, container, mesh bag, etc.).

Following shaving, milling or other technique whereby they are obtained,the bone material is subjected to demineralization in order to reduceits inorganic content to a very low level, in some embodiments, to notmore than about 5% by weight of residual calcium and preferably to notmore than about 1% by weight residual calcium. Demineralization of thebone material ordinarily results in its contraction to some extent.

Bone used in the methods described herein may be autograft, allograft,or xenograft. In various embodiments, the bone may be cortical bone,cancellous bone, or cortico-cancellous bone. While specific discussionis made herein to demineralized bone matrix, bone matrix treated inaccordance with the teachings herein may be non-demineralized,demineralized, partially demineralized, or surface demineralized. Thisdiscussion applies to demineralized, partially demineralized, andsurface demineralized bone matrix. In one embodiment, the demineralizedbone is sourced from bovine or human bone. In another embodiment,demineralized bone is sourced from human bone. In one embodiment, thedemineralized bone is sourced from the patient's own bone (autogenousbone). In another embodiment, the demineralized bone is sourced from adifferent animal (including a cadaver) of the same species (allograftbone).

Any suitable manner of demineralizing the bone may be used.Demineralization of the bone material can be conducted in accordancewith known conventional procedures. For example, in a preferreddemineralization procedure, the bone materials useful for theimplantable composition of this application are subjected to an aciddemineralization step that is followed by a defatting/disinfecting step.The bone material is immersed in acid over time to effect itsdemineralization. Acids which can be employed in this step includeinorganic acids such as hydrochloric acid and organic acids such asperacetic acid, acetic acid, citric acid, or propionic acid. The depthof demineralization into the bone surface can be controlled by adjustingthe treatment time, temperature of the demineralizing solution,concentration of the demineralizing solution, agitation intensity duringtreatment, and other applied forces such as vacuum, centrifuge,pressure, and other factors such as known to those skilled in the art.Thus, in various embodiments, the bone material may be fullydemineralized, partially demineralized, or surface demineralized.

After acid treatment, the bone is rinsed with sterile water forinjection, buffered with a buffering agent to a final predetermined pHand then finally rinsed with water for injection to remove residualamounts of acid and buffering agent or washed with water to removeresidual acid and thereby raise the pH. Following demineralization, thebone material is immersed in solution to effect its defatting. Apreferred defatting/disinfectant solution is an aqueous solution ofethanol, the ethanol being a good solvent for lipids and the water beinga good hydrophilic carrier to enable the solution to penetrate moredeeply into the bone. The aqueous ethanol solution also disinfects thebone by killing vegetative microorganisms and viruses. Ordinarily atleast about 10 to 40 weight percent by weight of water (i.e., about 60to 90 weight percent of defatting agent such as alcohol) should bepresent in the defatting/disinfecting solution to produce optimal lipidremoval and disinfection within the shortest period of time. Thepreferred concentration range of the defatting solution is from about 60to 85 weight percent alcohol and most preferably about 70 weight percentalcohol.

Further in accordance with this application, the DBM material can beused immediately for preparation of the implant composition or it can hestored under aseptic conditions, advantageously in a critical pointdried state prior to such preparation. In a preferred embodiment, thehone material can retain some of its original mineral content such thatthe composition is rendered capable of being imaged utilizingradiographic techniques.

In various embodiments, this application also provides bone matrixcompositions comprising critical point drying (CPD) fibers. DBM includesthe collagen matrix of the bone together with acid insoluble proteinsincluding bone morphogenic proteins (BMPs) and other growth factors. Itcan be formulated for use as granules, gels, sponge material or puttyand can be freeze-dried for storage. Sterilization procedures used toprotect from disease transmission may reduce the activity of beneficialgrowth factors in the DBM. DBM provides an initial osteoconductivematrix and exhibits a degree of osteoinductive potential, inducing theinfiltration and differentiation of osteoprogenitor cells from thesurrounding tissues.

DBM preparations have been used for many years in orthopedic medicine topromote the formation of bone. For example, DBM has found use in therepair of fractures, in the fusion of vertebrae, in joint replacementsurgery, and in treating bone destruction due to underlying disease suchas rheumatoid arthritis. DBM is thought to promote bone formation invivo by osteoconductive and osteoinductive processes. The osteoinductiveeffect of implanted DBM compositions is thought to result from thepresence of active growth factors present on the isolated collagen-basedmatrix. These factors include members of the TGF-β, IGF, and BMP proteinfamilies. Particular examples of osteoinductive factors include TGF-β,IGF-1, IGF-2, BMP-2, BMP-7, parathyroid hormone (PTH), and angiogenicfactors. Other osteoinductive factors such as osteocalcin andosteopontin are also likely to be present in DBM preparations as well.There are also likely to be other unnamed or undiscovered osteoinductivefactors present in DBM.

In various embodiments, the DBM provided in the methods described inthis application is prepared from elongated bone fibers which have beensubjected to critical point drying. The elongated CPD bone fibersemployed in this application are generally characterized as havingrelatively high average length to average width ratios, also known asthe aspect ratio. In various embodiments, the aspect ratio of theelongated bone fibers is at least from about 50:1 to about at leastabout 1000:1. Such elongated bone fibers can be readily obtained by anyone of several methods, for example, by milling or shaving the surfaceof an entire bone or relatively large section of bone.

In other embodiments, the length of the fibers can be at least about 3.5cm and average width from about 20 mm to about 1 cm. In variousembodiments, the average length of the elongated fibers can be fromabout 3.5 cm to about 6.0 cm and the average width from about 20 mm toabout 1 cm. In other embodiments, the elongated fibers can have anaverage length be from about 4.0 cm to about 6.0 cm and an average widthfrom about 20 mm to about 1 cm.

In yet other embodiments, the diameter or average width of the elongatedfibers is, for example, not more than about 1.00 cm, not more than 0.5cm or not more than about 0.01 cm. In still other embodiments, thediameter or average width of the fibers can be from about 0.01 cm toabout 0.4 cm or from about 0.02 cm to about 0.3 cm.

In another embodiment, the aspect ratio of the fibers can be from about50:1 to about 950:1, from about 50:1 to about 750:1, from about 50:1 toabout 500:1, from about 50:1 to about 250:1; or from about 50:1 to about100:1. Fibers according to this disclosure can advantageously have anaspect ratio from about 50:1 to about 1000:1, from about 50:1 to about950:1, from about 50:1 to about 750:1, from about 50:1 to about 600:1,from about 50:1 to about 350:1, from about 50:1 to about 200:1, fromabout 50:1 to about 100:1, or from about 50:1 to about 75:1.

In some embodiments, the chips to fibers ratio is about 90:10, 80:20,70:30, 60:40, 50:50, 40:60, 30:70, 20:80 and/or 10:90. In variousembodiments, a surface demineralized chips to fibers ratio is about90:10, 80:20, 70:30. 60:40, 50:50, 40:60, 30:70, 20:80 and/or 10:90. Insome embodiments, a surface demineralized chips to fully demineralizedfibers ratio is about 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70,20:80 and/or 10:90.

In some embodiments, the DBM fibers have a thickness of about 0.5-4 mm.In various embodiments, the DBM fibers have a thickness of about 0.5,0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5 and/or 4 mm. In variousembodiments, the ratio of DBM fibers to DBM powder is about 40:60 toabout 90:10 W/W, W/V or V/V. In some embodiments, the ratio ofmineralized bone fibers to DBM powder is about 25:75 to about 75:25 W/W,W/V or V/V. In various embodiments, the device comprises DBM fibers andmineralized fibers in a ratio of 40:60 to about 90:10 W/W, W/V or V/V.In some embodiments, the DBM fibers to DBM powder ratio, mineralizedbone fibers to DBM powder ratio and/or the DBM fibers and mineralizedfibers ratio is from 5:95 to about 95:5 W/W, W/V or V/V. In someembodiments, the DBM fibers to DBM powder ratio, mineralized bone fibersto DBM powder ratio and/or the DBM fibers and mineralized fibers ratiois 5:95, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50,55:45, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 90:10 and/or 95:5 W/W,W/V or V/V.

In some embodiments, the bone material comprises demineralized bonematerial comprising demineralized bone, fibers, powder, chips,triangular prisms, spheres, cubes, cylinders, shards or other shapeshaving irregular or random geometries. These can include, for example,“substantially demineralized,” “partially demineralized,” or “fullydemineralized” cortical and/or cancellous bone. These also includesurface demineralization, where the surface of the bone construct issubstantially demineralized, partially demineralized, or fullydemineralized, yet the body of the bone construct is fully mineralized.

In various embodiments, the bone graft material comprises fully DBMfibers and surface demineralized bone chips. In some embodiments, theratio of fully DBM fibers to surface demineralized bone chips is from5:95 to about 95:5 fibers to chips. In some embodiments, the ratio offully DBM fibers to surface demineralized bone chips is 5:95, 10:90,15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 55:45, 60:40,65:35, 70:30, 75:25, 80:20, 85:15, 90:10 and/or 95:5 fibers to chips. Invarious embodiments, the fully DBM fibers have a thickness of about0.5-4 mm. In various embodiments, the fully DBM fibers have a thicknessof about 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5 and/or 4 mm.

In various embodiments, the fibers and/or the powder is surface DBM. Insome embodiments, the fibers and/or the powder is surface DBM corticalallograft. In various embodiments, surface demineralization involvessurface demineralization to at least a certain depth. For example, thesurface demineralization of the of the allograft can be from about 0.25mm, 0.5 mm, 1 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4 mm, 4.5 mm,to about 5 mm. The edges of the bone fibers and/or powder may further bemachined into any shape or to include features such as grooves,protrusions, indentations, etc., to help improve fit and limit anymovement or micromotion to help fusion and/or osteoinduction to occur.

To prepare the osteogenic DBM, a quantity of fibers is combined with abiocompatible carrier to provide a demineralized bone matrix.

DBM typically is dried, for example via lyophilization or solventdrying, to store and maintain the DBM in active condition forimplantation. Moreover, each of these processes is thought to reduce theoverall surface area structure of bone. As may be appreciated, thestructural damage of the exterior surface reduces the overall surfacearea. Physical alterations to the surface and reduction in surface areacan affect cell attachment, mobility, proliferation, anddifferentiation. The surface's affinity for growth factors and releasekinetics of growth factors from the surface may also be altered.

Accordingly, in some embodiments, methods for drying bone to store andmaintain the bone in active condition for implantation that maintains orincreases the surface area of the bone are provided. In one embodiment,the bone matrix is treated using critical point drying (CPD) technique,thereby reducing destruction of the surface of the bone. While specificdescription is made to critical point drying, it is to be appreciatedthat, in alternative embodiments, super critical point treatment may beused. In various embodiments utilizing CPD, a percentage of collagenfibrils on the surface of the bone are non-denatured after drying to aresidual moisture content of approximately 15% or less. In someembodiments, after drying, the bone matrix has a residual moisturecontent of approximately 8% or less. In some embodiments, after drying,the bone matrix has a residual moisture content of approximately 6% orless. In some embodiments, after drying, the bone matrix has a residualmoisture content of approximately 6% or less. In some embodiments, afterdrying, the bone matrix has a residual moisture content of approximately3% or less.

Evaporative drying and freeze drying of specimens can cause deformationand collapse of surface structures, leading to a decrease in surfacearea. Without wishing to be bound to a particularly theory, thisdeformation and structure is thought to be caused because, as asubstance crosses the boundary from liquid to gas, the substancevolatilizes such that the volume of the liquid decreases. As thishappens, surface tension at the solid-liquid interface pulls against anystructures to which the liquid is attached. Delicate surface structurestend to be broken apart by this surface tension. Such damage may becaused by the effects of surface tension on the liquid/gas interface.Critical point drying is a technique that avoids effects of surfacetension on the liquid/gas interface by substantially preventing aliquid/gas interface from developing. Critical point or supercriticaldrying does not cross any phase boundary, instead passing through thesupercritical region, where the distinction between gas and liquidceases to apply. As a result, materials dehydrated using critical pointdrying are not exposed to damaging surface tension forces. When thecritical point of the liquid is reached, it is possible to pass fromliquid to gas without abrupt change in state. Critical point drying canbe used with bone matrices to phase change from liquid to dry gaswithout the effects of surface tension. Accordingly, bone dehydratedusing critical point drying can retain or increase at least some of thesurface structure and therefore the surface area.

In some embodiments, critical point drying is carried out using carbondioxide. However, other mediums such as Freon, including Freon 13(chlorotrifluoromethane), may be used. Generally, fluids suitable forsupercritical drying include carbon dioxide (critical point 304.25 K at7.39 MPa or 31.1° C. at 1072 psi or 31.2° C. and 73.8 bar) and Freon(about 300 K at 3.5-4 MPa or 25 to 30° C. at 500-600 psi). Nitrous oxidehas similar physical behavior to carbon dioxide, but is a powerfuloxidizer in its supercritical state. Supercritical water is also apowerful oxidizer, partly because its critical point occurs at such ahigh temperature (374° C.) and pressure (3212 psi/647K and 22.064 MPa).

In some embodiments, the bone may be pretreated to remove water prior tocritical point drying. Thus, in accordance with one embodiment, bonematrix is dried using carbon dioxide in (or above) its critical pointstatus. After demineralization, bone matrix samples (in water) may bedehydrated to remove residual water content. Such dehydration may be,for example, through a series of graded ethanol solutions (for example,20%, 50%, 70%, 80%, 90%, 95%, 100% ethanol in deionized water). In someembodiments, penetrating the tissue with a graded series of ethanolsolutions or alcohols may be accomplished in an automated fashion. Forexample, pressure and vacuum could be used to accelerate penetrationinto the tissue.

In alternative embodiments, other means or procedures for removing water(drying or dehydrating) from the bone may be used. For example, the bonemay be washed with other dehydrating liquids such as acetone to removewater, exploiting the complete miscibility of these two fluids. Theacetone may then be washed away with high pressure liquid carbondioxide.

In some embodiments, the dehydrated bone matrix is placed in a chamberwithin a critical point drying (CPD) apparatus and flushed with liquidCO₂ to remove ethanol (or other dehydrating liquid). Flushing withliquid CO₂ may be done one or more times. The temperature and/orpressure are then raised to the critical point (the critical point forCO₂ is reached at 31.2° C. and 73.8 bar). To perform critical pointdrying, the temperature and pressure may continue to be raised, forexample to 40° C. with corresponding pressure of 85 bar. Thus, in someembodiments, the liquid carbon dioxide is heated until its pressure isat or above the critical point, at which time the pressure can begradually released, allowing the gas to escape and leaving a driedproduct.

In certain embodiments, bone fibers processed using CPD have a BETsurface area from about 1 to about 5 m²/gm, a value 3 or 4 times greaterthan lyophilized bone fibers. In other embodiments, DBM fibers processedusing CPD have a BET area surface from about 40 to about 100 m²/gm, avalue 100 times greater than when DBM fibers are lyophilized.

In a further embodiment, the critical point dried samples may further betreated, or alternatively be treated, with supercritical carbon dioxide(carbon dioxide above the critical point). Supercritical CO₂ may also beuseful in viral inactivation. In some embodiments, thus, the bone matrixis placed in a supercritical CO₂ chamber and liquid CO₂ is introduced,for example, by an air pump. The temperature is raised to 105° C. withcorresponding pressure about 485 bar. In alternative embodiments, othertemperatures and/or pressures above the critical point of CO₂ may beused. The samples are soaked in supercritical CO₂ for a certain time andCO₂ is released. The resulting bone samples retain surface morphologies,hence surface area, and osteoinductivity after such treatment.

In yet a further embodiment, monolithic bone is demineralized andparticulated before drying. Accordingly, the bone may be demineralizedin monolithic pieces. The demineralized monolithic pieces may then bemilled in a wet condition and critical point dried, for example usingcarbon dioxide as a medium.

In yet a further embodiment, monolithic bone is demineralized and driedbefore particulating (if done). Accordingly, the bone may bedemineralized in monolithic pieces. The DBM is pressed in a wetcondition and then critical point dried, for example using carbondioxide as a medium. In alternatives of this embodiment, thedemineralized and dried monolithic bone is not particulated and isprocessed as a monolithic implant.

Methods of Making

In various embodiments as shown in FIG. 10, a method 200 of fabricatinga hollow structure, such as a mesh bag 70, through use of a 3D printingdevice 10 is provided. In some embodiments, the method includes step 210for inputting instructions for a processor 102 to carry out thefabrication, step 220 for aligning the printing surface, base and printhead relative to one another, step 230 for depositing material onto theprinting surface, step 240 for rotating the printing surface and movingthe base to create a mesh pattern, and step 250 for solidifying materialon the printing surface, and step 260 for forming and removing the meshbag. In some embodiments, the method comprises: rotating a print surfacein alternating clockwise and counterclockwise directions, ejectingmaterial from a print head to the print surface to make a strand havinga wave-like pattern with alternating peaks and crests, and rotating theprint head such an angular distance to create a plurality ofinterconnected strands on the print surface.

In some embodiments, a method for fabricating a hollow structure isprovided which includes providing a 3D printing machine 10 having atable 14, a base 16 and a printing surface 12. In various embodiments,printing surface 12 is rotatable about an axis of rotation. Base 16 isconfigured for planar movement. Printing surface 12 is fixedly disposedwith table 14 such that lateral movement of base 16 causes lateralmovement of printing surface 12. In some embodiments, base 16 is movablein the x-y plane and is laterally movable in both the x axis and the yaxis for precise positioning of printing surface 12. Movement of base 16allows for positioning of printing surface 12 relative to extensionshaft 20 to facilitate depositing materials onto printing surface 12, asdiscussed herein. 3D printing device 10 further includes a print head 30to deposit material 40 onto printing surface 12.

In some embodiments, a processor 102 receives instructions for thefabrication of a mesh bag 70. A user may input instructions directlyinto 3D printing device 10 or may input instructions into an externalcomputer in communication with processor 102. Processor 102 directsmovement of base 16, printing surface 12 and print head 30 relative toone another. Processor 102 also directs application of material 40 fromprint head 30 onto printing surface 12.

In some embodiments, a user loads a material reservoir (not shown) incommunication with print head 30 with a suitable material 40. Thematerial may be in powder form, particulate form, gel form, or solidform. Processor 102 moves the printing surface 12 and one or more printheads 30 into place relative to one another. Once positioned, print headbegins to deposit material 40 onto printing surface 12. In someembodiments, print head 30 continuously deposits material 40 as printingsurface 12 is rotated and/or moved laterally along the x-y plane. Insome embodiments, printing surface 12 is rotated in the clockwise andcounterclockwise directions while base 16 moves laterally to formwave-shaped strands 72. The degree of rotation may be adjusted to impartflexible and stretchable qualities onto each of the formed strands 72.For example, strands 72 having shorter wavelengths will be able to bestretched more than strands 72 having longer wavelengths. In someembodiments, processor 102 directs rotation of printing surface 12 andlateral movement of base 16 to impart stretchability of mesh bag 70 thatis uniform across its length. In some embodiments, processor 102 directsvariable rotation of printing surface 12 and lateral movement of base 16such that mesh bag 70 includes regions of increased stretchabilityaccording to the needs of a surgical application.

The movement of base 16, printing surface 12 and print head 30 relativeto one another and the application of material 40 onto printing surface12 is repeated a number of times such that strands 72 encompass thesurface of printing surface 12. That is, each time a strand having awave-like shape is applied to printing surface 12, a similar strand 72is applied to printing surface 12 adjacent the first strand. In someembodiments, strands 72 are extruded adjacent to one another such thatthe peaks of a first strand 72 are extruded to contact the crest of anadjacent second strand 72. In some embodiments, the mesh bag may becreated entirely from strands 72 having this configuration.

In some embodiments, print head 30 deposits material 40 in powdered formto printing surface 12. The material 40 must be sintered and/or meltedto form strands 72. In some embodiments, a radiation source, such aslaser 60 may be used in conjunction with print head 30. Processor 102directs laser 60 to be focused at a point on which material 40 has beendeposited adjacent print head 30. Processor 102 also provides power tolaser 60 during desired intervals to prevent unwanted damage to mesh bag70 and/or printing surface 12 according to the instructions. That is,laser 60 will emit a beam while sintering material 40 to create strands72, but will not emit a beam when printing surface 12 is beingrepositioned relative to print head 30. Once all desired sintering hasbeen completed, any excess material 40 may be brushed away from printingsurface 12 to be discarded or recycled.

In some embodiments, material 40 may be sintered through use of aheating unit 50. Heating unit 50 provides energy to printing surface 12such that powdered material 40 melts and molds together. An amount ofheat may be provided such that the material 40 melts quickly uponcontact with printing surface 12.

In some embodiments, printing surface 12 is heated or cooled usingtemperature control unit 50 to remove mesh bag 70. In some embodiments,printing surface 12 may be removed from 3D printing device 10 andsubmerged in a solvent to loosen and remove mesh bag 70.

As shown in FIG. 9, a computer-implemented method for producing a hollowstructure such as a mesh bag is illustrated. In a first step 110, a useror a designer generates an image of the object to be created with the 3Dprinting machine, such as, for example, mesh bag 70. Commerciallyavailable CAM software can make the CAD drawing/design of the medicalimplant into a computer code, (e.g., g-code). This code is sent to thedevice and the controller controls the device and the loading of theprint head with the material, the heating and cooling temperature andtime of the material, laser emit time, rotation, rotation speed of theprint surface, print head, table, lateral movement of the print surface,print head, and table as well as other parameters. The controller devicecreates a medical implant from or in the material.

In a second step 112, processor 102 calculates the X, Y, Z and A axes.The device employs Cartesian coordinate system (X, Y, Z) for 3D motioncontrol and employs a 4th axis (A) for the rotation of the print surface(e.g., 360 degrees) relative to the print head. The implant can bedesigned virtually in the computer with a CAD/CAM program, which is on acomputer display. The user inputs specific parameters into the computerand then presses print on the display to start the 3D printingmanufacturing. The computer logic causes the computer to execute loadingof the print head with the material, application and thickness of thepolymer from print head, the heating and cooling temperature and time ofthe device, laser emit time, rotation, rotation speed of the: printsurface, print head, and/or print table, and/or lateral movement of theprint surface, print head, and/or table as well as other parameters inaccordance with the received instructions. The controller device causesthe print head to be located at the appropriate X, Y, Z coordinates for3D motion control and employs a 4th axis (A) for the rotation of theprint surface (e.g., 360 degrees, 180 degrees, 120 degrees) relative tothe print head to make a medical implant from or in the material. Afterthe medical implant is produced on all or a portion of the printsurface, it will have a hollow region which typically is greater thanthe diameter or thickness of the print surface and can be removed by atool that engages the print surface. In some embodiments, the device canhave a tool to seal, etch, shape, and/or dry the implant before, duringor after it is removed from the print surface.

In a third step 114, processor 102 calculates the polymer applicationlocation and speed by planning coordination of the printing surface 12and print head 30. Unlike typical 3D printing, in some embodiments, thecurrent device does not manufacture the implant device by printing insuccessive layers the material to form the implant. In a fourth step 116and a fifth step 118, processor 102 calculates the rotation of printsurface 12 and the lateral and/or backward and forward movement ofprinting surface 12 and print head 30. In some embodiments, the printsurface of the current application has the polymer continuouslydispensed from the print head and onto the print surface as the printsurface rotates in 360 degrees clockwise and/or counterclockwiserelative to the print head and the print table, and/or print surfacecan, in some embodiments, move in a forward, lateral, and/or backwarddirection so that the strands to make the medical implant (e.g., meshbag) are formed in accordance with the instructions received from thecomputer. In some embodiments, the print surface of the currentapplication has a heat sensitive polymer disposed on it and then theprint head receives instructions to heat the surface area to be removed(e.g., by laser, heating element, etc.). In this way, strands of thepolymer are made by removing the heated portions of the polymer and whatis left on the print surface are the strands for the implant. The printsurface rotates in 360 degrees clockwise and/or counterclockwiserelative to the print head and the print table, and/or print surfacecan, in some embodiments, move in a forward, lateral, and/or backwarddirection so that the strands to make the medical implant (e.g., meshbag) are formed as the rest of the polymer is remove from the printsurface in accordance with the instructions received from the computer.

In some embodiments, the print surface of the current application hasthe polymer in dry powder form continuously dispensed from the printhead and onto the print surface as the print surface rotates in 360degrees clockwise and/or counterclockwise relative to the print head andthe print table, and/or print surface can, in some embodiments, move ina forward, lateral, and/or backward direction so that the strands tomake the medical implant (e.g., mesh bag) are formed in accordance withthe instructions received from the computer. After, the powderapplication, which can be from the print head from a reservoir therein,the print head (e.g., laser, heating element coupled thereto) can heatthe powder polymer and form the strands for the medical implant.

Based on the above calculations, processor 102 calculates a projectedamount of time it will take to manufacture the medical implant in step120. In a subsequent step 122, processor 102 calculates the amount oftime it will take for the printed medical device to dry. In someembodiments, the material applied to printing surface is temperaturesensitive and dries and/or cures through heating or cooling. In someembodiments, processor 120 directs a temperature control unit to heat orcool printing surface 12. In some embodiments, processor 120 directs alaser to focus its beam on the material applied to printing surface 12to sinter and cure the material.

In step 124, the data calculated by processor 102 is stored in memory100 for subsequent implementation. In some embodiments, processor 102processes and organizes the calculated data into memory 100. In someembodiments, processor 100 includes value-determining logic, developmentlogic, security logic, and/or analytical logic. In some embodiments,processor 102 updates the memory 100 with any new calculation datareceived from the user. In some embodiments, there is a computerreadable storage medium storing instructions that, when executed by acomputer, cause the computer to display options for a user to enter,view, and edit some or all features for manufacturing the implantincluding the loading of the print head with the material, the heatingand cooling temperature and time of the material, laser emit time,rotation angle, rotation speed of the print surface, print head, table,lateral movement of the print surface, print head, and table as well asother parameters. The controller device creates a medical implant fromor in the material by instructions received from the computer. Thedevice employs Cartesian coordinate system (X, Y, Z) for 3D motioncontrol and employs a 4th axis (A) for the rotation of the print surface(e.g., 360 degrees) relative to the print head.

In a final step 126, the user inputs a command to send the stored datato the printer to create the medical device. The user inputs specificparameters into the computer and then presses print on the display tostart the 3D printing manufacturing. The computer logic causes thecomputer to execute loading of the print head with the material, theheating and cooling temperature and time of the device, laser emit time,rotation, rotation speed of the: print surface, print head, and/or printtable, and/or lateral movement of the print surface, print head, and/ortable as well as other parameters. The controller device causes theprint head to be located at the appropriate X, Y, Z coordinates for 3Dmotion control and employs a 4th axis (A) for the rotation of the printsurface (e.g., 360 degrees, 180 degrees, 120 degrees) relative to theprint head to make a medical implant from or in the material.

Any suitable method may be used for loading a bone material into themesh bag in the operating room or at the surgical site. In someembodiments, the bone material may be spooned into the mesh bag, thesubstance may be placed in the mesh bag body using forceps, thesubstance may be loaded into the mesh bag using a syringe (with orwithout a needle), or the substance may be inserted into the mesh bag inany other suitable manner. Specific embodiments for loading at thesurgical site include for vertebroplasty or for interbody space filler.

For placement, the substance or substances may be provided in the meshbag and placed in vivo, for example at a bone defect. In one embodiment,the mesh bag is placed in vivo by placing the mesh bag in a catheter ortubular inserter and delivering the mesh bag with the catheter ortubular inserter. The mesh bag, with a substance provided therein, maybe steerable such that it can be used with flexible introducerinstruments for, for example, minimally invasive spinal procedures. Forexample, the osteoimplant may be introduced down a tubular retractor orscope, during XLIF, TLIF, or other procedures. In other embodiments, themesh bag (with or without substance loaded) may be placed in a cage, forexample for interbody fusion.

In some embodiments, the mesh bag may be prefilled with a substance fordelivery and other compartments may be empty for filling by the surgeon.

The mesh bag may be used in any suitable application. In someembodiments, the mesh bag may be used in healing vertebral compressionfractures, interbody fusion, minimally invasive procedures,posterolateral fusion, correction of adult or pediatric scoliosis,treating long bone defects, osteochondral defects, ridge augmentation(dental/craniomaxillofacial, e.g. edentulous patients), beneath traumaplates, tibial plateau defects, filling bone cysts, wound healing,around trauma, contouring (cosmetic/plastic/reconstructive surgery), andothers. The mesh bag may be used in a minimally invasive procedure viaplacement through a small incision, via delivery through a tube, orother. The size and shape may be designed with restrictions on deliveryconditions.

In some embodiments, the mesh bag is flexible enough so that it can befolded upon itself before it is implanted at, near or in the bonedefect.

An exemplary application for using a mesh bag as disclosed is fusion ofthe spine. In clinical use, the mesh bag and delivered substance may beused to bridge the gap between the transverse processes of adjacent orsequential vertebral bodies. The mesh bag may be used to bridge two ormore spinal motion segments. The mesh bag surrounds the substance to beimplanted, and contains the substance to provide a focus for healingactivity in the body.

Generally, the mesh bag may be applied to a pre-existing defect, to acreated channel, or to a modified defect. Thus, for example, a channelmay be formed in a bone, or a pre-existing defect may be cut to form achannel, for receipt of the device. The mesh bag may be configured tomatch the channel or defect. In some embodiments, the configuration ofthe mesh bag may be chosen to match the channel. In other embodiments,the channel may be created, or the defect expanded or altered, toreflect a configuration of the mesh bag. The mesh bag may be placed inthe defect or channel and, optionally, coupled using attachmentmechanisms.

Although the invention has been described with reference to preferredembodiments, persons skilled in the art will recognize that changes maybe made in form and detail without departing from the spirit and scopeof the invention.

1-18. (canceled)
 19. A method for making an implant having a hollowregion, the method comprising applying a material used to make theimplant having the hollow region on a device having a print surfacerotatable in clockwise and counterclockwise directions about an axis ofrotation, a print head disposed adjacent to and substantially transverseto the print surface, the print head configured to apply a material usedto make the implant on at least a portion of the print surface or heatmaterial applied on at least the portion of the print surface used tomake the implant, a base disposed adjacent to the print head andcontacting the print surface, the base configured to be movable inforward, backward and lateral directions relative to the print head tomake the implant having the hollow region.
 20. The method for making animplant having a hollow region of claim 19, wherein the material isapplied to the print surface by the print head and by rotating the printsurface in alternating clockwise and counterclockwise directions to makea strand of the material having a wave-like pattern with alternatingpeaks and crests, and rotating the print head such an angular distanceto make a plurality of interconnected strands of the material on theprint surface.
 21. The method for making an implant having a hollowregion of claim 19, wherein the device further comprises a processorconfigured to receive instructions for moving the base, print surfaceand print head to make the implant having the hollow region.
 22. Themethod for making an implant having a hollow region of claim 19, wherein(i) the print head continuously applies the material on a portion of theprint surface; (ii) the print surface is centered about the axis ofrotation; (iii) the print surface is disposed with the base via amounting bracket, the mounting bracket comprising an extension shaft,the extension shaft defining the axis of rotation for the print surface;or (iv) the print head is immovable and positioned above the printsurface.
 23. The method for making an implant having a hollow region ofclaim 19, wherein the material comprises (i) a biodegradable polymerconfigured to be printed into a mesh bag, the mesh bag having no sealsin its upper and lower portion; or (ii) a biodegradable polymer being inpowder form configured to be applied to the print surface and heated bythe print head to make the implant.
 24. The method for making an implanthaving a hollow region of claim 19, wherein the biodegradable polymerscomprise poly(lactic acid), poly(glycolic acid), poly(lacticacid-glycolic acid), polydioxanone, PVA, polyurethanes, polycarbonates,polyhydroxyalkanoates (polyhydroxybutyrates and polyhydroxyvalerates andcopolymers), polysaccharides, polyhydroxyalkanoatespolyglycolide-co-caprolactone, polyethylene oxide, polypropylene oxide,polyglycolide-co-trimethylene carbonate, poly(lactic-co-glycolic acid)or combinations thereof.
 25. The method for making an implant having ahollow region of claim 21, wherein (i) the processor is configured torotate the print surface relative to the print head and eject thematerial from the print head or (ii) a laser is disposed on the printhead to heat the material.
 26. The method for making an implant having ahollow region of claim 21, wherein the processor is configured to rotatethe print surface up to 360 degrees relative to the print head and tomelt or remove the material from the print surface.
 27. The method formaking an implant having a hollow region of claim 19, wherein the tableis configured to move in the backward and forward direction in asubstantially straight line and the lateral direction in a substantiallystraight line.
 28. The method for making an implant having a hollowregion of claim 19, further comprising a temperature control unitcoupled to the print head and/or print surface configured to affect thetemperature of the print head and/or print surface.
 29. The method formaking an implant having a hollow region of claim 28, wherein thetemperature control unit comprises a heating unit or a cooling unit. 30.The method for making an implant having a hollow region of claim 19,wherein the print surface is textured or coated with an adhesivematerial.
 31. The method for making an implant having a hollow region ofclaim 19, wherein the print surface is movable between an expandedconfiguration and a contracted configuration.
 32. A method for making animplant having a hollow region, the method comprising applying amaterial used to make the implant having the hollow region on a devicecomprising a print surface rotatable in a clockwise and counterclockwisedirection about an axis of rotation relative to a print head, and atleast one of (i) the print surface configured to be movable in forwardand backward directions relative to the print head or (ii) the printhead configured to be movable in forward and backward directionsrelative to the print surface, the print head disposed adjacent to andsubstantially transverse to the print surface; and the print headconfigured to apply material used to make the implant on at least aportion of the print surface or heat material disposed on at least aportion of the print surface used to make the implant having the hollowregion.
 33. The method for making an implant having a hollow region ofclaim 32, wherein the device further comprises a processor configured toreceive instructions for moving the base, print surface and print headto make the implant having the hollow region.
 34. The method for makingan implant having a hollow region of claim 32, wherein (i) the printhead also moves in a lateral direction side to side relative to theprint surface or (ii) a laser is disposed on the print head to heat thematerial.
 35. The method for making an implant having a hollow region ofclaim 32, wherein the material comprises (i) a biodegradable polymerconfigured to be printed into a mesh bag, the mesh bag having no sealsin its upper and lower portion; or (ii) a biodegradable polymer being inpowder form configured to be applied to the print surface and heated bythe print head to make the implant.
 36. The method for making an implanthaving a hollow region of claim 35, wherein the biodegradable polymerscomprise poly(lactic acid), poly(glycolic acid), poly(lacticacid-glycolic acid), polydioxanone, PVA, polyurethanes, polycarbonates,polyhydroxyalkanoates (polyhydroxybutyrates and polyhydroxyvalerates andcopolymers), polysaccharides, polyhydroxyalkanoatespolyglycolide-co-caprolactone, polyethylene oxide, polypropylene oxide,polyglycolide-co-trimethylene carbonate, poly(lactic-co-glycolic acid)or combinations thereof.
 37. The method for making an implant having ahollow region of claim 33, wherein the processor is configured to rotatethe print surface up to 360 degrees relative to the print head and tomelt or remove the material from the print surface.
 38. Acomputer-implemented method for creating a hollow structure, the methodcomprising inputting instructions to direct a processor, the processorconfigured to induce rotation of a print surface in alternatingclockwise and counterclockwise directions, and ejection of material froma print head to the print surface to make a strand having a wave-likepattern with alternating peaks and crests, and rotating the print headsuch an angular distance to create a plurality of interconnected strandson the print surface.
 39. The computer-implemented method for creating ahollow structure of claim 38, wherein the hollow structure is a meshbag.